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Sample records for antagonizes icp4-dependent silencing

  1. Silencing the alarms: innate immune antagonism by rotavirus NSP1 and VP3

    Science.gov (United States)

    Morelli, Marco; Ogden, Kristen M.; Patton, John T.

    2016-01-01

    The innate immune response involves a broad array of pathogen sensors that stimulate the production of interferons (IFN) to induce an antiviral state. Rotavirus, a significant cause of childhood gastroenteritis and a member of the Reoviridae family of segmented, double-stranded RNA viruses, encodes at least two direct antagonists of host innate immunity: NSP1 and VP3. NSP1, a putative E3 ubiquitin ligase, mediates the degradation of cellular factors involved in both IFN induction and downstream signaling. VP3, the viral capping enzyme, utilizes a 2H-phosphodiesterase domain to prevent activation of the cellular oligoadenylate synthase (OAS)-RNase L pathway. Computational, molecular, and biochemical studies have provided key insights into the structural and mechanistic basis of innate immune antagonism by NSP1 and VP3 of group A rotaviruses (RVA). Future studies with non-RVA isolates will be essential to understand how other RV species evade host innate immune responses. PMID:25724417

  2. Silence multiple

    DEFF Research Database (Denmark)

    Søndergaard, Katia Dupret

    The article highlights the importance of silences in the processes of innovation in organizations, and the claim is that silence and the absence of talk distribute authority, responsibility and decisions. The act of silencing is conceptualised as a central “configurating actor”. Using an Actor......-Network Theoretical approach to organization studies silence is conceptualised as both a means and an effect of innovative efforts. It is a way of ordering practices. Thus silencing is thought of as a central potential change agent both in composing a kind of specific organizational collectivity and in composing new...... working practices more generally. In line with the approach to destabilise the mundane, invisible and taken-for-granted aspects of innovative efforts in organisations (crucial for ANT and foucauldian post-structuralism more broadly), this article suggests to non-silence the silence and make...

  3. Bacterial Associations: Antagonism to Symbiosis

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.

    , such as endosymbiosis and antagonism. Commensalism ?Commensalism? was derived from the Latin term ?com mensa? meaning ?sharing a table?. In Commensalism, one-organism benefits and the other is neither harmed nor helped. Commensalism represents a simple type of positive...

  4. Evolutionary inevitability of sexual antagonism.

    Science.gov (United States)

    Connallon, Tim; Clark, Andrew G

    2014-02-07

    Sexual antagonism, whereby mutations are favourable in one sex and disfavourable in the other, is common in natural populations, yet the root causes of sexual antagonism are rarely considered in evolutionary theories of adaptation. Here, we explore the evolutionary consequences of sex-differential selection and genotype-by-sex interactions for adaptation in species with separate sexes. We show that sexual antagonism emerges naturally from sex differences in the direction of selection on phenotypes expressed by both sexes or from sex-by-genotype interactions affecting the expression of such phenotypes. Moreover, modest sex differences in selection or genotype-by-sex effects profoundly influence the long-term evolutionary trajectories of populations with separate sexes, as these conditions trigger the evolution of strong sexual antagonism as a by-product of adaptively driven evolutionary change. The theory demonstrates that sexual antagonism is an inescapable by-product of adaptation in species with separate sexes, whether or not selection favours evolutionary divergence between males and females.

  5. My Day of Silence.

    Science.gov (United States)

    Brown, Scott C.

    1999-01-01

    A heterosexual doctoral student discusses his experiences when he tries to take part in a day of silence to help combat homophobia and heterosexism. His vow of silence teaches him that he will never fully understand the experience of a person who has been historically, socially, and legally silent. (Author/MKA)

  6. Silencing criticism in Mexico

    Directory of Open Access Journals (Sweden)

    Ximena Suárez

    2017-10-01

    Full Text Available Journalists and human rights defenders in Mexico are being attacked in an attempt to silence their criticism. Many are forced to flee or risk being assassinated. The consequences are both personal and of wider social significance.

  7. Ombuds’ corner: Employee silence

    CERN Multimedia

    Vincent Vuillemin

    2013-01-01

    Although around a hundred cases a year are reported to the Ombuds, several issues may still not be disclosed due to employee silence*. The deliberate withholding of concerns, escalating misunderstandings or genuine conflicts can impede the global process of learning and development of a better respectful organizational workplace environment, and prevent the detection and correction of acts violating the CERN Code of Conduct.   For the employee him/herself, such silence can lead to feelings of anger, resentment, helplessness and humiliation. These feelings will inevitably contaminate personal and interpersonal relations, and poison creativity and effectiveness. Employee silence can be explained by many factors; sometimes it is connected to organizational forces. In their published paper*, authors Michael Knoll and Rolf van Dick found four forms of employee silence. People may stay silent if they feel that their opinion is neither welcomed nor valued by their management. They have gi...

  8. Memories Persist in Silence

    Directory of Open Access Journals (Sweden)

    Sandra Patricia Arenas Grisales

    2012-08-01

    Full Text Available This article exposes the hypothesis that memory artifacts, created to commemorate the victims of armed conflict in Colombia, are an expression of the underground memories and a way of political action in the midst of war. We analyze three cases of creations of memory artifacts in Medellín, Colombia, as forms of suffering, perceiving and resisting the power of armed groups in Medellín. The silence, inherent in these objects, should not be treated as an absence of language, but as another form of expression of memory. Silence is a tactic used to overcome losses and reset everyday life in contexts of protracted violence.

  9. Methods for antagonizing glutamate neurotoxicity.

    Science.gov (United States)

    Choi, D W

    1990-01-01

    Recent evidence suggests that glutamate-induced neuronal damage may contribute importantly to neuronal death in several neurological diseases, including cerebral hypoxia-ischemia. This review outlines a range of measures that might be used to protect neurons from such excitotoxic damage. The organizing thesis is a speculative consideration of glutamate neurotoxicity as a sequential three-stage process--induction, amplification, and expression--each perhaps specifically amenable to therapeutic interference. Overstimulation of glutamate receptors likely induces the intracellular accumulation of several substances, including Ca2+, Na+, inositol-1,4,5-trisphosphate, and diacylglycerol. Blockade of this induction might be accomplished most easily by antagonizing postsynaptic glutamate receptors, but also might be accomplished by reducing glutamate release from presynaptic terminals, or improving glutamate clearance from synaptic clefts. Following induction, several steps may importantly amplify the resultant rise in intracellular free Ca2+, and promote the spread of excessive excitation to other circuit neurons. Protective strategies operative at this level might include blockade of additional Ca2+ influx, blockade of Ca2+ release from intracellular stores, and interference with the mechanisms coupling glutamate receptor stimulation to lasting enhancements of excitatory synaptic efficacy. Following amplification, toxic levels of intracellular free Ca2+ might trigger destructive cascades bearing direct responsibility for resultant neuronal degeneration--the expression of excitotoxicity. The most important cascades to block may be those related to the activation of catabolic enzymes, and the generation of free radicals. Broad consideration of possible methods for antagonizing glutamate neurotoxicity may be needed to develop therapies with the greatest efficacy, and least adverse consequences for brain function.

  10. The Fruit of Silence

    Science.gov (United States)

    Nelson, Marilyn

    2006-01-01

    This presentation explores how contemplative practices, especially those anchored in an active listening to silence, are integrated into creative writing courses. It pays particular attention to a course taught at the United States Military Academy at West Point and to a course on the poetry of war and peace taught at the University of…

  11. Silence of the Genes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 4. Silence of the Genes - 2006 Nobel Prize in Physiology or Medicine. Utpal Nath Saumitra Das. General Article Volume 12 Issue 4 April 2007 pp 6-18. Fulltext. Click here to view fulltext PDF. Permanent link:

  12. Silence of the Genes

    Indian Academy of Sciences (India)

    Srimath

    The human genome codes for ~35,000 genes and all these genes are not expressed in every cell. The time and site of gene expression is very precisely regulated. In any cell, only. Silence of the Genes. 2006 Nobel Prize in Physiology or Medicine. Utpal Nath and Saumitra Das. Keywords. RNA interference, siRNA,.

  13. Antagonism of acetylcholine by adrenaline antagonists

    Science.gov (United States)

    Benfey, B. G.; Grillo, S. A.

    1963-01-01

    Phenoxybenzamine antagonized the inhibitory action of acetylcholine on the guinea-pig isolated atrium. The antagonism was slow in onset, very slowly reversible, and could be overcome by increased concentrations of acetylcholine. In contrast, atropine inhibited the action of acetylcholine quickly, and the effect disappeared soon after withdrawal. The pA10 of phenoxybenzamine (2 hr of contact) was 6.8, and that of atropine (30 min of contact) was 8.4. In the presence of atropine phenoxybenzamine did not exert a slowly reversible antagonism, and the dose-ratio of acetylcholine returned to normal soon after withdrawal of both drugs. Phenoxybenzamine also antagonized acetylcholine in the guinea-pig isolated ileum, but with higher concentrations acetylcholine did not overcome the antagonism. The pA10 (60 min of contact) was 6.6. The pA10 of chlorpromazine in the atrium (2 hr of contact) and ileum (60 min of contact) was 5.9. Phentolamine, 2-diethylaminomethylbenzo-1,4-dioxan hydrochloride (883 F), and yohimbine antagonized acetylcholine in the atrium and ileum but required higher concentrations than chlorpromazine. PMID:13967429

  14. Antisense gene silencing

    DEFF Research Database (Denmark)

    Nielsen, Troels T; Nielsen, Jørgen E

    2013-01-01

    Since the first reports that double-stranded RNAs can efficiently silence gene expression in C. elegans, the technology of RNA interference (RNAi) has been intensively exploited as an experimental tool to study gene function. With the subsequent discovery that RNAi could also be applied...... to mammalian cells, the technology of RNAi expanded from being a valuable experimental tool to being an applicable method for gene-specific therapeutic regulation, and much effort has been put into further refinement of the technique. This review will focus on how RNAi has developed over the years and how...

  15. Memories Persist in Silence

    OpenAIRE

    Sandra Patricia Arenas Grisales

    2012-01-01

    This article exposes the hypothesis that memory artifacts, created to commemorate the victims of armed conflict in Colombia, are an expression of the underground memories and a way of political action in the midst of war. We analyze three cases of creations of memory artifacts in Medellín, Colombia, as forms of suffering, perceiving and resisting the power of armed groups in Medellín. The silence, inherent in these objects, should not be treated as an absence of language, but as another form ...

  16. Voice and silence in organizations

    Directory of Open Access Journals (Sweden)

    Moaşa, H.

    2011-01-01

    Full Text Available Unlike previous research on voice and silence, this article breaksthe distance between the two and declines to treat them as opposites. Voice and silence are interrelated and intertwined strategic forms ofcommunication which presuppose each other in such a way that the absence of one would minimize completely the other’s presence. Social actors are not voice, or silence. Social actors can have voice or silence, they can do both because they operate at multiple levels and deal with multiple issues at different moments in time.

  17. "Listening Silence" and Its Discursive Effects

    Science.gov (United States)

    Applebaum, Barbara

    2016-01-01

    While researchers have studied how white silence protects white innocence and white ignorance, in this essay Barbara Applebaum explores a form of white silence that she refers to as "listening silence" in which silence protects white innocence but does not necessarily promote resistance to learning. White listening silence can appear to…

  18. Bodies, Spaces, Voices, Silences

    Directory of Open Access Journals (Sweden)

    Donatella Mazzoleni

    2013-07-01

    Full Text Available A good architecture should not only allow functional, formal and technical quality for urban spaces, but also let the voice of the city be perceived, listened, enjoyed. Every city has got its specific sound identity, or “ISO” (R. O. Benenzon, made up of a complex texture of background noises and fluctuation of sound figures emerging and disappearing in a game of continuous fadings. For instance, the ISO of Naples is characterized by a spread need of hearing the sound return of one’s/others voices, by a hate of silence. Cities may fall ill: illness from noise, within super-crowded neighbourhoods, or illness from silence, in the forced isolation of peripheries. The proposal of an urban music therapy denotes an unpublished and innovative enlarged interdisciplinary research path, where architecture, music, medicine, psychology, communication science may converge, in order to work for rebalancing spaces and relation life of the urban collectivity, through the care of body and sound dimensions.

  19. Organizational Silence in Sports Employees

    Science.gov (United States)

    Bastug, Gulsum; Pala, Adem; Yilmaz, Taner; Duyan, Mehdi; Gunel, Ilker

    2016-01-01

    Organizational silence can be defined as a way of behaviour belonging to men and women employees in the organization exhibited without reflecting their feelings, ideas, concerns and suggestions related with their workplaces, works for which they are responsible or other activities of the organization. In the period of organizational silence,…

  20. Silence, an Eye of Knowledge

    Science.gov (United States)

    Aghamohammadi, Mehdi

    2017-01-01

    One of the conspicuous features of the twentieth-century West was silence. This idea could be supported by examining reflections of Ludwig Wittgenstein, Fritz Mauthner, John Cage, Samuel Beckett, Ihab Hassan, Franz Kafka, Wassily Kandinsky, Jean-Paul Sartre, Virginia Woolf, Wolfgang Iser, Jacques Derrida, and Pierre Macherey. To me, silence is not…

  1. Silence, an Eye of Knowledge

    Directory of Open Access Journals (Sweden)

    Mehdi Aghamohammadi

    2017-04-01

    Full Text Available One of the conspicuous features of the twentieth-century West was silence. This idea could be supported by examining reflections of Ludwig Wittgenstein, Fritz Mauthner, John Cage, Samuel Beckett, Ihab Hassan, Franz Kafka, Wassily Kandinsky, Jean-Paul Sartre, Virginia Woolf, Wolfgang Iser, Jacques Derrida, and Pierre Macherey. To me, silence is not a mere theory, but rather a phenomenon from which we can get practical benefits. I believe silence is an eye, eye of knowledge. We can broaden our knowledge of the world through silence. To convey the idea that silence is an eye, I have concocted the word slence, where  has replaced the letter i and stands for the eye. This means knowledge can enable us to see, thereby acquiring knowledge of, what used to be invisible, and accordingly unknowable. In other words, through silence, we can achieve a certain type of literacy. I substantiate this claim by exploring the Horus myth, Ojo de Dios, John Cage’s 4' 33", the nature of Expressionist paintings, Hinduism, thoughts of Hermes Trismegistus and Ibn al-Arabi, and practices of Mohammad, the prophet of Islam.

  2. Identification and mechanism of ABA receptor antagonism

    Energy Technology Data Exchange (ETDEWEB)

    Melcher, Karsten; Xu, Yong; Ng, Ley-Moy; Zhou, X. Edward; Soon, Fen-Fen; Chinnusamy, Viswanathan; Suino-Powell, Kelly M; Kovach, Amanda; Tham, Fook S.; Cutler, Sean R.; Li, Jun; Yong, Eu-Leong; Zhu, Jian-Kang; Xu, H. Eric (NU Sinapore); (Van Andel); (UCR)

    2010-11-11

    The phytohormone abscisic acid (ABA) functions through a family of fourteen PYR/PYL receptors, which were identified by resistance to pyrabactin, a synthetic inhibitor of seed germination. ABA activates these receptors to inhibit type 2C protein phosphatases, such as ABI1, yet it remains unclear whether these receptors can be antagonized. Here we demonstrate that pyrabactin is an agonist of PYR1 and PYL1 but is unexpectedly an antagonist of PYL2. Crystal structures of the PYL2-pyrabactin and PYL1-pyrabactin-ABI1 complexes reveal the mechanism responsible for receptor-selective activation and inhibition, which enables us to design mutations that convert PYL1 to a pyrabactin-inhibited receptor and PYL2 to a pyrabactin-activated receptor and to identify new pyrabactin-based ABA receptor agonists. Together, our results establish a new concept of ABA receptor antagonism, illustrate its underlying mechanisms and provide a rational framework for discovering novel ABA receptor ligands.

  3. Triclosan antagonizes fluconazole activity against Candida albicans.

    LENUS (Irish Health Repository)

    Higgins, J

    2012-01-01

    Triclosan is a broad-spectrum antimicrobial compound commonly used in oral hygiene products. Investigation of its activity against Candida albicans showed that triclosan was fungicidal at concentrations of 16 mg\\/L. However, at subinhibitory concentrations (0.5-2 mg\\/L), triclosan antagonized the activity of fluconazole. Although triclosan induced CDR1 expression in C. albicans, antagonism was still observed in cdr1Δ and cdr2Δ strains. Triclosan did not affect fluconazole uptake or alter total membrane sterol content, but did induce the expression of FAS1 and FAS2, indicating that its mode of action may involve inhibition of fatty acid synthesis, as it does in prokaryotes. However, FAS2 mutants did not exhibit increased susceptibility to triclosan, and overexpression of both FAS1 and FAS2 alleles did not alter triclosan susceptibility. Unexpectedly, the antagonistic effect was specific for C. albicans under hypha-inducing conditions and was absent in the non-filamentous efg1Δ strain. This antagonism may be due to the membranotropic activity of triclosan and the unique composition of hyphal membranes.

  4. Triclosan Antagonizes Fluconazole Activity against Candida albicans

    Science.gov (United States)

    Higgins, J.; Pinjon, E.; Oltean, H.N.; White, T.C.; Kelly, S.L.; Martel, C.M.; Sullivan, D.J.; Coleman, D.C.; Moran, G.P.

    2012-01-01

    Triclosan is a broad-spectrum antimicrobial compound commonly used in oral hygiene products. Investigation of its activity against Candida albicans showed that triclosan was fungicidal at concentrations of 16 mg/L. However, at subinhibitory concentrations (0.5-2 mg/L), triclosan antagonized the activity of fluconazole. Although triclosan induced CDR1 expression in C. albicans, antagonism was still observed in cdr1Δ and cdr2Δ strains. Triclosan did not affect fluconazole uptake or alter total membrane sterol content, but did induce the expression of FAS1 and FAS2, indicating that its mode of action may involve inhibition of fatty acid synthesis, as it does in prokaryotes. However, FAS2 mutants did not exhibit increased susceptibility to triclosan, and overexpression of both FAS1 and FAS2 alleles did not alter triclosan susceptibility. Unexpectedly, the antagonistic effect was specific for C. albicans under hypha-inducing conditions and was absent in the non-filamentous efg1Δ strain. This antagonism may be due to the membranotropic activity of triclosan and the unique composition of hyphal membranes. PMID:21972257

  5. Convergent evolution of argonaute-2 slicer antagonism in two distinct insect RNA viruses.

    Directory of Open Access Journals (Sweden)

    Joël T van Mierlo

    Full Text Available RNA interference (RNAi is a major antiviral pathway that shapes evolution of RNA viruses. We show here that Nora virus, a natural Drosophila pathogen, is both a target and suppressor of RNAi. We detected viral small RNAs with a signature of Dicer-2 dependent small interfering RNAs in Nora virus infected Drosophila. Furthermore, we demonstrate that the Nora virus VP1 protein contains RNAi suppressive activity in vitro and in vivo that enhances pathogenicity of recombinant Sindbis virus in an RNAi dependent manner. Nora virus VP1 and the viral suppressor of RNAi of Cricket paralysis virus (1A antagonized Argonaute-2 (AGO2 Slicer activity of RNA induced silencing complexes pre-loaded with a methylated single-stranded guide strand. The convergent evolution of AGO2 suppression in two unrelated insect RNA viruses highlights the importance of AGO2 in antiviral defense.

  6. WIF1 is a frequent target for epigenetic silencing in squamous cell carcinoma of the cervix

    OpenAIRE

    Delmas, Amber L.; Riggs, Bridget M.; Pardo, Carolina E.; Dyer, Lisa M.; Darst, Russell P.; Izumchenko, Eugene G.; Monroe, Mänette; Hakam, Ardeshir; Kladde, Michael P.; Siegel, Erin M.; Brown, Kevin D.

    2011-01-01

    Aberrant activation of the Wnt/β-catenin signaling axis is a prominent oncogenic mechanism in numerous cancers including cervical cancer. Wnt inhibitory factor-1 (WIF1) is a secreted protein that binds Wnt and antagonizes Wnt activity. While the WIF1 gene is characterized as a target for epigenetic silencing in some tumor types, WIF1 expression has not been examined in human cervical tissue and cervical cancer. Here, we show that WIF1 is unmethylated and its gene product is expressed in norma...

  7. Antagonism correlates with metabolic similarity in diverse bacteria.

    Science.gov (United States)

    Russel, Jakob; Røder, Henriette L; Madsen, Jonas S; Burmølle, Mette; Sørensen, Søren J

    2017-10-03

    In the Origin of Species , Charles R. Darwin [Darwin C (1859) On the Origin of Species ] proposed that the struggle for existence must be most intense among closely related species by means of their functional similarity. It has been hypothesized that this similarity, which results in resource competition, is the driver of the evolution of antagonism among bacteria. Consequently, antagonism should mostly be prevalent among phylogenetically and metabolically similar species. We tested the hypothesis by screening for antagonism among all possible pairwise interactions between 67 bacterial species from 8 different environments: 2,211 pairs of species and 4,422 interactions. We found a clear association between antagonism and phylogenetic distance, antagonism being most likely among closely related species. We determined two metabolic distances between our strains: one by scoring their growth on various natural carbon sources and the other by creating metabolic networks of predicted genomes. For both metabolic distances, we found that the probability of antagonism increased the more metabolically similar the strains were. Moreover, our results were not compounded by whether the antagonism was between sympatric or allopatric strains. Intriguingly, for each interaction the antagonizing strain was more likely to have a wider metabolic niche than the antagonized strain: that is, larger metabolic networks and growth on more carbon sources. This indicates an association between an antagonistic and a generalist strategy.

  8. Communicative Silences: Forms and Functions

    Science.gov (United States)

    Bruneau, Thomas J.

    1973-01-01

    The nature of silence is discussed as an imposition of mind, as an interdependent signification ground for speech signs, as a relationship to mental time (as opposed to artificial time), and as it relates to sensation, perception and metaphorical movement. (Author)

  9. Silence in the creative process

    Directory of Open Access Journals (Sweden)

    Francesco Wilhelm

    2015-01-01

    Full Text Available A research about silence as the moment where creative thinking takes place, as an art object and as a way of interpreting artworks, is the main issue of the graduation thesis named Il silenzio nel processo creativo (2014. Here is proposed an offprint, which summarizes its fundamental steps.

  10. The silence of the archive

    CERN Document Server

    Thomas, David; Thomas, David

    2017-01-01

    This new book will provide a ground breaking discussion of a major but little considered issue - the silence of the archive: why archives, sometimes seen as the repositories of truth, often fail to satisfy users because they do not contain information which they expect to find.

  11. Breaching cultural silence: enhancing resilience among Ugandan ...

    African Journals Online (AJOL)

    Cultural silence is frequently the outcome of deep-seated taboos regarding adults talking to children about sex and death. This paper examines the impact of cultural silence on the resilience of children orphaned by AIDS in Uganda. Cultural silence is often linked with denial. This article explores the complexities of cultural ...

  12. Identification and mechanism of ABA receptor antagonism

    KAUST Repository

    Melcher, Karsten

    2010-08-22

    The phytohormone abscisic acid (ABA) functions through a family of fourteen PYR/PYL receptors, which were identified by resistance to pyrabactin, a synthetic inhibitor of seed germination. ABA activates these receptors to inhibit type 2C protein phosphatases, such as ABI1, yet it remains unclear whether these receptors can be antagonized. Here we demonstrate that pyrabactin is an agonist of PYR1 and PYL1 but is unexpectedly an antagonist of PYL2. Crystal structures of the PYL2-pyrabactin and PYL1-pyrabactin-ABI1 complexes reveal the mechanism responsible for receptor-selective activation and inhibition, which enables us to design mutations that convert PYL1 to a pyrabactin-inhibited receptor and PYL2 to a pyrabactin-activated receptor and to identify new pyrabactin-based ABA receptor agonists. Together, our results establish a new concept of ABA receptor antagonism, illustrate its underlying mechanisms and provide a rational framework for discovering novel ABA receptor ligands. © 2010 Nature America, Inc. All rights reserved.

  13. Transcriptional Silencing of Retroviral Vectors

    DEFF Research Database (Denmark)

    Lund, Anders Henrik; Duch, M.; Pedersen, F.S.

    1996-01-01

    Although retroviral vector systems have been found to efficiently transduce a variety of cell types in vitro, the use of vectors based on murine leukemia virus in preclinical models of somatic gene therapy has led to the identification of transcriptional silencing in vivo as an important problem....... Extinction of long-term vector expression has been observed after implantation of transduced hematopoietic cells as well as fibroblasts, myoblasts and hepatocytes. Here we review the influence of vector structure, integration site and cell type on transcriptional silencing. While down-regulation of proviral...... transcription is known from a number of cellular and animal models, major insight has been gained from studies in the germ line and embryonal cells of the mouse. Key elements for the transfer and expression of retroviral vectors, such as the viral transcriptional enhancer and the binding site for the t...

  14. Agonism and antagonism at the insulin receptor

    DEFF Research Database (Denmark)

    Knudsen, Louise; Hansen, Bo Falck; Jensen, Pia

    2012-01-01

    Insulin can trigger metabolic as well as mitogenic effects, the latter being pharmaceutically undesirable. An understanding of the structure/function relationships between insulin receptor (IR) binding and mitogenic/metabolic signalling would greatly facilitate the preclinical development of new...... insulin analogues. The occurrence of ligand agonism and antagonism is well described for G protein-coupled receptors (GPCRs) and other receptors but in general, with the exception of antibodies, not for receptor tyrosine kinases (RTKs). In the case of the IR, no natural ligand or insulin analogue has been...... shown to exhibit antagonistic properties, with the exception of a crosslinked insulin dimer (B29-B'29). However, synthetic monomeric or dimeric peptides targeting sites 1 or 2 of the IR were shown to be either agonists or antagonists. We found here that the S961 peptide, previously described to be an IR...

  15. Forced Normalization: Antagonism Between Epilepsy and Psychosis.

    Science.gov (United States)

    Kawakami, Yasuhiko; Itoh, Yasuhiko

    2017-05-01

    The antagonism between epilepsy and psychosis has been discussed for a long time. Landolt coined the term "forced normalization" in the 1950s to describe psychotic episodes associated with the remission of seizures and disappearance of epileptiform activity on electroencephalograms in individuals with epilepsy. Since then, neurologists and psychiatrists have been intrigued by this phenomenon. However, although collaborative clinical studies and basic experimental researches have been performed, the mechanism of forced normalization remains unknown. In this review article, we present a historical overview of the concept of forced normalization, and discuss potential pathogenic mechanisms and clinical diagnosis. We also discuss the role of dopamine, which appears to be a key factor in the mechanism of forced normalization. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Posttranscriptional gene silencing in nuclei

    Science.gov (United States)

    Hoffer, Paul; Ivashuta, Sergey; Pontes, Olga; Vitins, Alexa; Pikaard, Craig; Mroczka, Andrew; Wagner, Nicholas; Voelker, Toni

    2011-01-01

    In plants, small interfering RNAs (siRNAs) with sequence homology to transcribed regions of genes can guide the sequence-specific degradation of corresponding mRNAs, leading to posttranscriptional gene silencing (PTGS). The current consensus is that siRNA-mediated PTGS occurs primarily in the cytoplasm where target mRNAs are localized and translated into proteins. However, expression of an inverted-repeat double-stranded RNA corresponding to the soybean FAD2-1A desaturase intron is sufficient to silence FAD2-1, implicating nuclear precursor mRNA (pre-mRNA) rather than cytosolic mRNA as the target of PTGS. Silencing FAD2-1 using intronic or 3′-UTR sequences does not affect transcription rates of the target genes but results in the strong reduction of target transcript levels in the nucleus. Moreover, siRNAs corresponding to pre-mRNA–specific sequences accumulate in the nucleus. In Arabidopsis, we find that two enzymes involved in PTGS, Dicer-like 4 and RNA-dependent RNA polymerase 6, are localized in the nucleus. Collectively, these results demonstrate that siRNA-directed RNA degradation can take place in the nucleus, suggesting the need for a more complex view of the subcellular compartmentation of PTGS in plants. PMID:21173264

  17. [E. M. Jellinek's silenced and silencing transgenerational story].

    Science.gov (United States)

    Kelemen, Gábor; Márk, Mónika

    2013-01-01

    Jellinek is a kind of archetypal character for future generations in the field of addiction studies. His implosion in the arena of alcoholism around the age of 50 was an unexpected challenge to medical science. We know very little about his own role models giving an intellectual and moral compass to his pragmatic creativity. More than 30 years has passed since Jellinek's death when an American sociologist Ron Roizen started unearthing his silent story. Roizen discerned that there are a lot of unsaid and muted issues in his personal Hungarian past. Our paper, based on the authors' research in Hungarian archives and other sources reveals that not just Jellinek's personal but his transgenerational narrative has been not-yet-said. This silenced and silencing history appears an unfinished business of acculturation of the family, which started prior to four generations. Authors have been concluding that the issue of religious conversion is a critical point in the process of acculturation. They examine the counter move of loyalty to family values and driving force of assimilation making their story unspeakable.

  18. Tat RNA silencing suppressor activity contributes to perturbation of lymphocyte miRNA by HIV-1

    Directory of Open Access Journals (Sweden)

    Yu Lianbo

    2011-05-01

    Full Text Available Abstract Background MicroRNA (miRNA-mediated RNA silencing is integral to virtually every cellular process including cell cycle progression and response to virus infection. The interplay between RNA silencing and HIV-1 is multifaceted, and accumulating evidence posits a strike-counterstrike interface that alters the cellular environment to favor virus replication. For instance, miRNA-mediated RNA silencing of HIV-1 translation is antagonized by HIV-1 Tat RNA silencing suppressor activity. The activity of HIV-1 accessory proteins Vpr/Vif delays cell cycle progression, which is a process prominently modulated by miRNA. The expression profile of cellular miRNA is altered by HIV-1 infection in both cultured cells and clinical samples. The open question stands of what, if any, is the contribution of Tat RNA silencing suppressor activity or Vpr/Vif activity to the perturbation of cellular miRNA by HIV-1. Results Herein, we compared the perturbation of miRNA expression profiles of lymphocytes infected with HIV-1NL4-3 or derivative strains that are deficient in Tat RNA silencing suppressor activity (Tat K51A substitution or ablated of the vpr/vif open reading frames. Microarrays recapitulated the perturbation of the cellular miRNA profile by HIV-1 infection. The miRNA expression trends overlapped ~50% with published microarray results on clinical samples from HIV-1 infected patients. Moreover, the number of miRNA perturbed by HIV-1 was largely similar despite ablation of Tat RSS activity and Vpr/Vif; however, the Tat RSS mutation lessened HIV-1 downregulation of twenty-two miRNAs. Conclusions Our study identified miRNA expression changes attributable to Tat RSS activity in HIV-1NL4-3. The results accomplish a necessary step in the process to understand the interface of HIV-1 with host RNA silencing activity. The overlap in miRNA expression trends observed between HIV-1 infected CEMx174 lymphocytes and primary cells supports the utility of cultured

  19. Silence

    Science.gov (United States)

    Cogswell, J.

    2011-06-01

    On the occasion of the International Year of Astronomy, I was commissioned to create a mural for the University of Michigan Department of Astronomy, responding to an array of scientific images based on astronomical research, with special focus on the work of University of Michigan astronomers carried out within the building. My paper illustrates the development of this and several subsequent projects, explaining the implications for my artistic practice of entering into this conversation with astronomers and their work.

  20. A Strategy for Antagonizing Quorum Sensing

    Energy Technology Data Exchange (ETDEWEB)

    G Chen; L Swem; D Swem; D Stauff; C OLoughlin; P Jeffrey; B Bassler; F Hughson

    2011-12-31

    Quorum-sensing bacteria communicate via small molecules called autoinducers to coordinate collective behaviors. Because quorum sensing controls virulence factor expression in many clinically relevant pathogens, membrane-permeable quorum sensing antagonists that prevent population-wide expression of virulence genes offer a potential route to novel antibacterial therapeutics. Here, we report a strategy for inhibiting quorum-sensing receptors of the widespread LuxR family. Structure-function studies with natural and synthetic ligands demonstrate that the dimeric LuxR-type transcription factor CviR from Chromobacterium violaceum is potently antagonized by molecules that bind in place of the native acylated homoserine lactone autoinducer, provided that they stabilize a closed conformation. In such conformations, each of the two DNA-binding domains interacts with the ligand-binding domain of the opposing monomer. Consequently, the DNA-binding helices are held apart by {approx}60 {angstrom}, twice the {approx}30 {angstrom} separation required for operator binding. This approach may represent a general strategy for the inhibition of multidomain proteins.

  1. "The Silence Itself Is Enough of a Statement": The Day of Silence and LGBTQ Awareness Raising

    Science.gov (United States)

    Woolley, Susan W.

    2012-01-01

    This ethnographic study of a high school gay-straight alliance club examines unintended consequences of silence during the Day of Silence, a day of action aimed at addressing anti-LGBTQ bias in schools. While this strategy calls for students to engage in intentional silences to raise awareness of anti-LGBTQ bias, it does not necessarily lead…

  2. Epigenetic Silencing and Resistance to Imatinib Mesylate in CML

    National Research Council Canada - National Science Library

    Issa, Jean-Pierre

    2004-01-01

    ...). In this project, we are exploring the hypothesis that epigenetic silencing associated with promoter DNA methylation mediates resistance in selected cases, and that reversal of silencing by decitabine...

  3. Epigenetic Silencing and Resistance to Imatinib Mesylate in CML

    National Research Council Canada - National Science Library

    Issa, Jean-Pierre

    2005-01-01

    ...). In this project, we are exploring the hypothesis that epigenetic silencing associated with promoter DNA methylation mediates resistance in selected cases, and that reversal of silencing by decitabine...

  4. Epigenetic Silencing and Resistance to Imatinib Mesylate in CML

    National Research Council Canada - National Science Library

    Issa, Jean-Pierre

    2006-01-01

    ...). In this project we are exploring the hypothesis that epigenetic silencing associated with promoter DNA methylation mediates resistance in selected cases and that reversal of silencing by decitabine...

  5. Personalized gene silencing therapeutics for Huntington disease.

    Science.gov (United States)

    Kay, C; Skotte, N H; Southwell, A L; Hayden, M R

    2014-07-01

    Gene silencing offers a novel therapeutic strategy for dominant genetic disorders. In specific diseases, selective silencing of only one copy of a gene may be advantageous over non-selective silencing of both copies. Huntington disease (HD) is an autosomal dominant disorder caused by an expanded CAG trinucleotide repeat in the Huntingtin gene (HTT). Silencing both expanded and normal copies of HTT may be therapeutically beneficial, but preservation of normal HTT expression is preferred. Allele-specific methods can selectively silence the mutant HTT transcript by targeting either the expanded CAG repeat or single nucleotide polymorphisms (SNPs) in linkage disequilibrium with the expansion. Both approaches require personalized treatment strategies based on patient genotypes. We compare the prospect of safe treatment of HD by CAG- and SNP-specific silencing approaches and review HD population genetics used to guide target identification in the patient population. Clinical implementation of allele-specific HTT silencing faces challenges common to personalized genetic medicine, requiring novel solutions from clinical scientists and regulatory authorities. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Yellow fever virus capsid protein is a potent suppressor of RNA silencing that binds double-stranded RNA.

    Science.gov (United States)

    Samuel, Glady Hazitha; Wiley, Michael R; Badawi, Atif; Adelman, Zach N; Myles, Kevin M

    2016-11-29

    Mosquito-borne flaviviruses, including yellow fever virus (YFV), Zika virus (ZIKV), and West Nile virus (WNV), profoundly affect human health. The successful transmission of these viruses to a human host depends on the pathogen's ability to overcome a potentially sterilizing immune response in the vector mosquito. Similar to other invertebrate animals and plants, the mosquito's RNA silencing pathway comprises its primary antiviral defense. Although a diverse range of plant and insect viruses has been found to encode suppressors of RNA silencing, the mechanisms by which flaviviruses antagonize antiviral small RNA pathways in disease vectors are unknown. Here we describe a viral suppressor of RNA silencing (VSR) encoded by the prototype flavivirus, YFV. We show that the YFV capsid (YFC) protein inhibits RNA silencing in the mosquito Aedes aegypti by interfering with Dicer. This VSR activity appears to be broadly conserved in the C proteins of other medically important flaviviruses, including that of ZIKV. These results suggest that a molecular "arms race" between vector and pathogen underlies the continued existence of flaviviruses in nature.

  7. The histone methyltransferases Set5 and Set1 have overlapping functions in gene silencing and telomere maintenance.

    Science.gov (United States)

    Jezek, Meagan; Gast, Alison; Choi, Grace; Kulkarni, Rushmie; Quijote, Jeremiah; Graham-Yooll, Andrew; Park, DoHwan; Green, Erin M

    2017-02-01

    Genes adjacent to telomeres are subject to transcriptional repression mediated by an integrated set of chromatin modifying and remodeling factors. The telomeres of Saccharomyces cerevisiae have served as a model for dissecting the function of diverse chromatin proteins in gene silencing, and their study has revealed overlapping roles for many chromatin proteins in either promoting or antagonizing gene repression. The H3K4 methyltransferase Set1, which is commonly linked to transcriptional activation, has been implicated in telomere silencing. Set5 is an H4 K5, K8, and K12 methyltransferase that functions with Set1 to promote repression at telomeres. Here, we analyzed the combined role for Set1 and Set5 in gene expression control at native yeast telomeres. Our data reveal that Set1 and Set5 promote a Sir protein-independent mechanism of repression that may primarily rely on regulation of H4K5ac and H4K8ac at telomeric regions. Furthermore, cells lacking both Set1 and Set5 have highly correlated transcriptomes to mutants in telomere maintenance pathways and display defects in telomere stability, linking their roles in silencing to protection of telomeres. Our data therefore provide insight into and clarify potential mechanisms by which Set1 contributes to telomere silencing and shed light on the function of Set5 at telomeres.

  8. The gifts of silence and solitude.

    Science.gov (United States)

    Schmidt Bunkers, Sandra

    2008-01-01

    In this column the author describes the importance of finding silence and solitude amid the noise and technology present today in the teaching-learning academy. Three gifts of silence and solitude are identified: the gift of comforting aloneness, the gift of vision for new horizons, and the gift of a sense of freedom. A humanbecoming perspective is used to explore the implications of these gifts. This column introduces a column by Diana Vander Woude describing her teaching-learning experience in leadership focusing on silence and solitude.

  9. Noncompetitive, Voltage-Dependent NMDA Receptor Antagonism by Hydrophobic Anions

    Science.gov (United States)

    Linsenbardt, Andrew J.; Chisari, Mariangela; Yu, Andrew; Shu, Hong-Jin; Zorumski, Charles F.

    2013-01-01

    NMDA receptor (NMDAR) antagonists are dissociative anesthetics, drugs of abuse, and are of therapeutic interest in neurodegeneration and neuropsychiatric disease. Many well-known NMDAR antagonists are positively charged, voltage-dependent channel blockers. We recently showed that the hydrophobic anion dipicrylamine (DPA) negatively regulates GABAA receptor function by a mechanism indistinguishable from that of sulfated neurosteroids. Because sulfated neurosteroids also modulate NMDARs, here we examined the effects of DPA on NMDAR function. In rat hippocampal neurons DPA inhibited currents gated by 300 µM NMDA with an IC50 of 2.3 µM. Neither onset nor offset of antagonism exhibited dependence on channel activation but exhibited a noncompetitive profile. DPA antagonism was independent of NMDAR subunit composition and was similar at extrasynaptic and total receptor populations. Surprisingly, similar to cationic channel blockers but unlike sulfated neurosteroids, DPA antagonism was voltage dependent. Onset and offset of DPA antagonism were nearly 10-fold faster than DPA-induced increases in membrane capacitance, suggesting that membrane interactions do not directly explain antagonism. Furthermore, voltage dependence did not derive from association of DPA with a site on NMDARs directly accessible to the outer membrane leaflet, assessed by DPA translocation experiments. Consistent with the expected lack of channel block, DPA antagonism did not interact with permeant ions. Therefore, we speculate that voltage dependence may arise from interactions of DPA with the inherent voltage dependence of channel gating. Overall, we conclude that DPA noncompetitively inhibits NMDA-induced current by a novel voltage-dependent mechanism and represents a new class of anionic NMDAR antagonists. PMID:23144238

  10. Small RNA-Mediated Epigenetic Myostatin Silencing

    Directory of Open Access Journals (Sweden)

    Thomas C Roberts

    2012-01-01

    Full Text Available Myostatin (Mstn is a secreted growth factor that negatively regulates muscle mass and is therefore a potential pharmacological target for the treatment of muscle wasting disorders such as Duchenne muscular dystrophy. Here we describe a novel Mstn blockade approach in which small interfering RNAs (siRNAs complementary to a promoter-associated transcript induce transcriptional gene silencing (TGS in two differentiated mouse muscle cell lines. Silencing is sensitive to treatment with the histone deacetylase inhibitor trichostatin A, and the silent state chromatin mark H3K9me2 is enriched at the Mstn promoter following siRNA transfection, suggesting epigenetic remodeling underlies the silencing effect. These observations suggest that long-term epigenetic silencing may be feasible for Mstn and that TGS is a promising novel therapeutic strategy for the treatment of muscle wasting disorders.

  11. Titration and hysteresis in epigenetic chromatin silencing

    Science.gov (United States)

    Dayarian, Adel; Sengupta, Anirvan M.

    2013-06-01

    Epigenetic mechanisms of silencing via heritable chromatin modifications play a major role in gene regulation and cell fate specification. We consider a model of epigenetic chromatin silencing in budding yeast and study the bifurcation diagram and characterize the bistable and the monostable regimes. The main focus of this paper is to examine how the perturbations altering the activity of histone modifying enzymes affect the epigenetic states. We analyze the implications of having the total number of silencing proteins, given by the sum of proteins bound to the nucleosomes and the ones available in the ambient, to be constant. This constraint couples different regions of chromatin through the shared reservoir of ambient silencing proteins. We show that the response of the system to perturbations depends dramatically on the titration effect caused by the above constraint. In particular, for a certain range of overall abundance of silencing proteins, the hysteresis loop changes qualitatively with certain jump replaced by continuous merger of different states. In addition, we find a nonmonotonic dependence of gene expression on the rate of histone deacetylation activity of Sir2. We discuss how these qualitative predictions of our model could be compared with experimental studies of the yeast system under anti-silencing drugs.

  12. Titration and hysteresis in epigenetic chromatin silencing

    International Nuclear Information System (INIS)

    Dayarian, Adel; Sengupta, Anirvan M

    2013-01-01

    Epigenetic mechanisms of silencing via heritable chromatin modifications play a major role in gene regulation and cell fate specification. We consider a model of epigenetic chromatin silencing in budding yeast and study the bifurcation diagram and characterize the bistable and the monostable regimes. The main focus of this paper is to examine how the perturbations altering the activity of histone modifying enzymes affect the epigenetic states. We analyze the implications of having the total number of silencing proteins, given by the sum of proteins bound to the nucleosomes and the ones available in the ambient, to be constant. This constraint couples different regions of chromatin through the shared reservoir of ambient silencing proteins. We show that the response of the system to perturbations depends dramatically on the titration effect caused by the above constraint. In particular, for a certain range of overall abundance of silencing proteins, the hysteresis loop changes qualitatively with certain jump replaced by continuous merger of different states. In addition, we find a nonmonotonic dependence of gene expression on the rate of histone deacetylation activity of Sir2. We discuss how these qualitative predictions of our model could be compared with experimental studies of the yeast system under anti-silencing drugs. (paper)

  13. Trichoderma spp. from rhizosphere soil and their antagonism ...

    African Journals Online (AJOL)

    One hundred and forty six (146) isolates of Trichoderma spp. were obtained from rhizosphere soils of potato plants in the middle areas of Gansu Province, China. By means of dual culture method, they were examined for antagonism against Fusarium sambucinum, which causes potato dry rot. Ten of the isolates were found ...

  14. The Impotence of Pseudo-Antagonism: A Derridean Response to ...

    African Journals Online (AJOL)

    The Impotence of Pseudo-Antagonism: A Derridean Response to Zizek\\'s Charge of Practical Irrelevance. A Hurst. Abstract. This article addresses a strange investment within 'continental' philosophy, in asserting the impotence of a Derridean approach when it comes to addressing practical (juridical, political, ethical, ...

  15. Rhubarb Antagonizes Matrix Metalloproteinase-9-induced Vascular Endothelial Permeability

    Directory of Open Access Journals (Sweden)

    Yun-Liang Cui

    2016-01-01

    Conclusions: The rhubarb mixture of emodin, 3,8-dihydroxy-1-methyl-anthraquinone-2-carboxylic acid, 1-O-caffeoyl-2-(4-hydroxyl-O-cinnamoyl-β-D-glucose, daucosterol linoleate, and rhein, at a low concentration, antagonized the MMP9-induced HUVEC monolayer permeability by promoting HUVEC proliferation and reducing extracellular VE-cadherin concentrations.

  16. Antagonism in the carbon footprint between beef and dairy ...

    African Journals Online (AJOL)

    The higher increase in production (milk) of intensive dairy cows, compared to the increase in production (calf weight) of intensive beef cows, explains the antagonism in the carbon footprint between different beef and dairy production systems. Unfortunately, carbon sequestration estimates have been neglected and thus the ...

  17. Molecular chaperones antagonize proteotoxicity by differentially modulating protein aggregation pathways

    OpenAIRE

    Douglas, Peter M; Summers, Daniel W; Cyr, Douglas M

    2009-01-01

    The self-association of misfolded or damaged proteins into ordered amyloid-like aggregates characterizes numerous neurodegenerative disorders. Insoluble amyloid plaques are diagnostic of many disease states. Yet soluble, oligomeric intermediates in the aggregation pathway appear to represent the toxic culprit. Molecular chaperones regulate the fate of misfolded proteins and thereby influence their aggregation state. Chaperones conventionally antagonize aggregation of misfolded, disease protei...

  18. Virus-induced gene silencing in detached tomatoes and biochemical effects of phytoene desaturase gene silencing

    NARCIS (Netherlands)

    Romero, I.; Tikunov, Y.M.; Bovy, A.G.

    2011-01-01

    Virus-induced gene silencing (VIGS) is a technology that has rapidly emerged for gene function studies in plants. Many advances have been made in applying this technique in an increasing number of crops. Recently, VIGS has been successfully used to silence genes in tomato fruit through

  19. Antagonism of type I interferon responses by new world hantaviruses.

    Science.gov (United States)

    Levine, Jessica R; Prescott, Joseph; Brown, Kyle S; Best, Sonja M; Ebihara, Hideki; Feldmann, Heinz

    2010-11-01

    Evasion of interferon (IFN)-mediated antiviral signaling is a common defense strategy for pathogenic RNA viruses. To date, research on IFN antagonism by hantaviruses is limited and has focused on only a subset of the numerous recognized hantavirus species. The host IFN response has two phases, an initiation phase, resulting in the induction of alpha/beta IFN (IFN-α/β), and an amplification phase, whereby IFN-α/β signals through the Jak/STAT pathway, resulting in the establishment of the cellular antiviral state. We examined interactions between these critical host responses and the New World hantaviruses. We observed delayed cellular responses in both Andes virus (ANDV)- and Sin Nombre virus (SNV)-infected A549 and Huh7-TLR3 cells. We found that IFN-β induction is inhibited by coexpression of ANDV nucleocapsid protein (NP) and glycoprotein precursor (GPC) and is robustly inhibited by SNV GPC alone. Downstream amplification by Jak/STAT signaling is also inhibited by SNV GPC and by either NP or GPC of ANDV. Therefore, ANDV- and SNV-encoded proteins have the potential for inhibiting both IFN-β induction and signaling, with SNV exhibiting the more potent antagonism ability. Herein we identify ANDV NP, a previously unrecognized inhibitor of Jak/STAT signaling, and show that IFN antagonism by ANDV relies on expression of both the glycoproteins and NP, whereas the glycoproteins appear to be sufficient for antagonism by SNV. These data suggest that IFN antagonism strategies by hantaviruses are quite variable, even between species with similar disease phenotypes, and may help to better elucidate species-specific pathogenesis.

  20. Spatiotemporal flicker detector model of motion silencing.

    Science.gov (United States)

    Choi, Lark Kwon; Bovik, Alan C; Cormack, Lawrence K

    2014-01-01

    Motion can impair the perception of other visual changes. Suchow and Alvarez (2011a, Current Biology, 21, 140-143) recently demonstrated a striking 'motion silencing' illusion, in which the salient changes among a group of objects' luminances (or colors, etc) appear to cease in the presence of large, coherent object motion. To understand why the visual system might be insensitive to changes in object luminances ('flicker') in the presence of object motion, we constructed similar stimuli and did a systematic spectral analysis of them. We conducted human psychophysical experiments to examine motion silencing as a function of stimulus velocity, flicker frequency, and spacing; and we created a simple filter-based model as a working hypothesis of motion silencing. From the results, we found that the threshold of silencing occurs when the log frequency of object replacement is roughly one quarter of the log flicker frequency (the mean slope is approximately 0.27). The dependence of silencing on object spacing may be explained as a phenomenon of temporal sampling of the stimuli by the visual system. Our proposed model successfully captures the psychophysical data over a wide range of velocities and flicker frequencies.

  1. Silence as a Response to Everyday Violence

    DEFF Research Database (Denmark)

    Gammeltoft, Tine

    2016-01-01

    Across the world, existing research indicates that many women respond with silence to marital abuse. This article offers an ethnographic investigation of the social and psychic forces behind Vietnamese women’s silencing of violence and a theoretical exploration of how the psychoanalytic concept...... of fantasy—understood as unconscious or subconscious mental processes—may contribute to the analysis of everyday violence and psychic distress. Distinguishing between what I term deliberate and subconscious silence, I explore the role that fantasy plays when Vietnamese women silently endure intimate partner...... violence. Closer ethnographic attention to the fantasy-constructions that sustain day-to-day lives can, I argue, strengthen the capacity of anthropology to comprehend how systems of everyday violence are upheld and rendered socially invisible....

  2. Active compressor engine silencer reduces exhaust noise

    International Nuclear Information System (INIS)

    Denenberg, J.N.; Miller, S.K.; Jay, M.A.

    1994-01-01

    An active industrial silencer on a compressor engine at a Tenneco Gas station has reduced low-frequency 'rumbling' noise by 8 dB during trials while lowering backpressure about 90$. This 8 dB reduction of the piston firing frequency corresponds to a more than 80% decrease in emitted acoustic power. The silencing unit, installed on one of six engines at the station near Eden, N.Y., continues in operation. Based on the results, the manufacturer is identifying additional compressor sites for further tests. This paper reviews this project

  3. “The Silence Itself is Enough of a Statement”: Unintended Consequences of Silence as an Awareness-Raising Strategy

    OpenAIRE

    Woolley, Susan W.

    2010-01-01

    The strategy of silence for voice, as seen in the Day of Silence, deploys silence in order to draw attention to the ways in which an individual or group has been silenced and to establish possibilities for voice. The Day of Silence is a nation-wide day of action aimed at addressing anti-LGBTQ bias and harassment in schools. This ethnographic study of a high school gay-straight alliance (GSA) club examines the unintended consequences of silence as an awareness-raising strategy during events ...

  4. Network structure embracing mutualism-antagonism continuums increases community robustness.

    Science.gov (United States)

    Montesinos-Navarro, Alicia; Hiraldo, Fernando; Tella, José L; Blanco, Guillermo

    2017-11-01

    Theory predicts that contrasting properties of mutualistic and antagonistic networks differentially promote community resilience to species loss. However, the outcome of most ecological interactions falls within a continuum between mutualism and antagonism, and we ignore the extent to which this interactions' continuum might influence community stability. Using a large data set of interactions, we compared co-extinction cascades that either consider or ignore the mix of beneficial and detrimental actions that parrots exert on plants. When the antagonism-mutualism continuum was considered, a combination of the properties that separately enhance community stability in ecological networks emerged. This combination of properties led to an overall increase of the parrot community robustness to face plant species loss. Our results highlight that the conditional outcomes of interactions can influence the structure of ecological networks, thus affecting our predictions of community stability against eventual changes.

  5. Interleukin-1 Antagonism Decreases Cortisol Levels in Obese Individuals

    OpenAIRE

    Urwyler, Sandrine Andrea; Schuetz, Philipp; Ebrahimi, Fahim; Donath, Marc Y.; Christ-Crain, Mirjam

    2017-01-01

    Increased cortisol levels in obesity may contribute to the associated metabolic syndrome. In obesity, the activated innate immune system leads to increased interleukin (IL)-1β, which is known to stimulate the release of adrenocorticotropin hormone (ACTH).; We hypothesized that in obesity IL-1 antagonism would result in downregulation of the hypothalamo-pituitary-adrenal axis, leading to decreased cortisol levels.; In this prospective intervention study, we included 73 patients with obesity (b...

  6. Surprised by Bird, Bard, and Bach: Language, Silence, and Transcendence.

    Science.gov (United States)

    Suhor, Charles

    1991-01-01

    Argues the importance of the relationships among silence and literature, the arts, and other experiences that point toward transcendence. Suggests that English teachers can expand the repertoire of classroom activities and teaching techniques that make use of silence. (KEH)

  7. Histone Methylation and Epigenetic Silencing in Breast Cancer

    National Research Council Canada - National Science Library

    Simon, Jeffrey A; Lange, Carol A

    2008-01-01

    .... EZH2 is a histone methyltransferase which modifies lysine-27 of histone H3 an epigenetic mark which is generally linked to gene silencing and is implicated in tumor suppressor silencing during breast cancer progression...

  8. Ethanol-induced hypothermia in rats is antagonized by dexamethasone

    Directory of Open Access Journals (Sweden)

    Carreño C.F.T.

    1997-01-01

    Full Text Available The effect of dexamethasone on ethanol-induced hypothermia was investigated in 3.5-month old male Wistar rats (N = 10 animals per group. The animals were pretreated with dexamethasone (2.0 mg/kg, ip; volume of injection = 1 ml/kg 15 min before ethanol administration (2.0, 3.0 and 4.0 g/kg, ip; 20% w/v and the colon temperature was monitored with a digital thermometer 30, 60 and 90 min after ethanol administration. Ethanol treatment produced dose-dependent hypothermia throughout the experiment (-1.84 ± 0.10, -2.79 ± 0.09 and -3.79 ± 0.15oC for 2.0, 3.0 and 4.0 g/kg ethanol, respectively, 30 min after ethanol but only the effects of 2.0 and 3.0 g/kg ethanol were significantly antagonized (-0.57 ± 0.09 and -1.25 ± 0.10, respectively, 30 min after ethanol by pretreatment with dexamethasone (ANOVA, P<0.05. These results are in agreement with data from the literature on the rapid antagonism by glucocorticoids of other effects of ethanol. The antagonism was obtained after a short period of time, suggesting that the effect of dexamethasone is different from the classical actions of corticosteroids

  9. Antagonism of Innate Immunity by Paramyxovirus Accessory Proteins

    Directory of Open Access Journals (Sweden)

    Raychel Chambers

    2009-10-01

    Full Text Available Paramyxovirinae, a subfamily of Paramyxoviridae, are negative strand RNA viruses comprised of many important human and animal pathogens, which share a high degree of genetic and structural homology. The accessory proteins expressed from the P/V/C gene are major factors in the pathogenicity of the viruses, because of their ability to abrogate various facets of type I interferon (IFN induction and signaling. Most of the paramyxoviruses exhibit a commonality in their ability to antagonize innate immunity by blocking IFN induction and the Jak/STAT pathway. However, the manner in which the accessory proteins inhibit the pathway differs among viruses. Similarly, there are variations in the capability of the viruses to counteract intracellular detectors (RNA helicases, mda-5 and RIG-I. Furthermore, a functional specificity in the antagonism of the IFN response has been reported, suggesting that specificity in the circumvention of innate immunity restricts viral host range. Available evidence indicates that paramyxoviruses employ specific strategies to antagonize the IFN response of their specific hosts, which is one of the major factors that determine viral pathogenicity and host range.

  10. Silence in the second language classroom

    CERN Document Server

    King, J

    2013-01-01

    Why are second language learners in Japan's universities so silent? This book investigates the perplexing but intriguing phenomenon of classroom silence and draws on ideas from psychology, sociolinguistics and anthropology to offer a unique insight into the reasons why some learners are either unable or unwilling to speak in a foreign language.

  11. Mainstream Television, Adolescent Homosexuality, and Significant Silence.

    Science.gov (United States)

    Kielwasser, Alfred P.; Wolf, Michelle A.

    1992-01-01

    Argues that the symbolic annihilation of gay and lesbian youth exhibited by network television contributes to a dysfunctional isolation supported by the mutually reinforcing invisibility of homosexual adolescents on television and in the real world. Suggests that the spiral of silence also partially accounts for the inefficacy of oppositional…

  12. From talking to silence: a confessional journey

    OpenAIRE

    Heddon, D.; Howells, A.

    2011-01-01

    This article provides an account of work created by Adrian Howells over the duration of his AHRC Creative Fellowship. Howells provides a creator's perspective; Heddon, a spectator's perspective. Both chart the shift from confessional performances anchored around speech, to the use of silence as a way to engage intimate connections between performer and audience.

  13. Detailed characterization of the posttranscriptional gene-silencing-related small RNA in a GUS gene-silenced tobacco

    NARCIS (Netherlands)

    Hutvágner, G.; Mlynarova, L.; Nap, J.P.H.

    2000-01-01

    Posttranscriptional gene-silencing phenomena such as cosuppression and RNA interference are associated with the occurrence of small, about 21-23 nt short RNA species homologous to the silenced gene. We here show that the small RNA present in silenced transgenic plants can easily be detected in total

  14. SIV Nef proteins recruit the AP-2 complex to antagonize Tetherin and facilitate virion release.

    OpenAIRE

    Fengwen Zhang; Wilmina N Landford; Melinda Ng; Matthew W McNatt; Paul D Bieniasz; Theodora Hatziioannou

    2011-01-01

    Lentiviral Nef proteins have multiple functions and are important for viral pathogenesis. Recently, Nef proteins from many simian immunodefiency viruses were shown to antagonize a cellular antiviral protein, named Tetherin, that blocks release of viral particles from the cell surface. However, the mechanism by which Nef antagonizes Tetherin is unknown. Here, using related Nef proteins that differ in their ability to antagonize Tetherin, we identify three amino-acids in the C-terminal domain o...

  15. Interleukin-1 Antagonism Decreases Cortisol Levels in Obese Individuals.

    Science.gov (United States)

    Urwyler, Sandrine Andrea; Schuetz, Philipp; Ebrahimi, Fahim; Donath, Marc Y; Christ-Crain, Mirjam

    2017-05-01

    Increased cortisol levels in obesity may contribute to the associated metabolic syndrome. In obesity, the activated innate immune system leads to increased interleukin (IL)-1β, which is known to stimulate the release of adrenocorticotropin hormone (ACTH). We hypothesized that in obesity IL-1 antagonism would result in downregulation of the hypothalamo-pituitary-adrenal axis, leading to decreased cortisol levels. In this prospective intervention study, we included 73 patients with obesity (body mass index [BMI] ≥30 kg/m2) and at least one additional feature of the metabolic syndrome. The primary end point was change in morning cortisol from baseline to after the administration of the IL-1 receptor antagonist (anakinra/Kineret®, total dose 3 × 100 mg). Secondary end points were effects on salivary cortisol and ACTH. Median age was 56 years, 50.7% of patients were female, and median BMI was 36.3 kg/m2. Median morning serum cortisol levels (nmol/L) decreased significantly after IL-1 antagonism [from baseline, 452 to 423; absolute difference, -38.7; 95% confidence interval (CI), -64 to -13.4; P = 0.0019]. Similar effects were found for salivary cortisol levels (-2.8; 95% CI, -4.4 to -1.3; P = 0.0007), ACTH levels (-2.2; 95% CI; -4.2 to -0.1; P = 0.038), systolic blood pressure (-5.2, 95% CI, -8.5 to -1.8; P = 0.0006), and heart rate (-2.9; 95% CI, -4.7 to -1.0; P = 0.0029). IL-1 antagonism in obese individuals with features of the metabolic syndrome leads to a decrease in serum cortisol, salivary cortisol, and ACTH levels along with a reduction in systolic blood pressure and heart rate. Copyright © 2017 Endocrine Society

  16. Break the silence: Let's talk about AIDS.

    Science.gov (United States)

    1999-10-11

    The organizers of the Confederation of East and Central Africa Football Associations¿ (CECAFA) Youth Tournament in Kenya will organize a campaign on AIDS prevention. ¿Break the Silence: Let¿s Talk About AIDS¿ is the campaign slogan, which will be used before, during, and after the 2-week football tournament. The campaign will involve an estimated 300 players and coaches and millions of fans who will attend, watch television, or listen to radios. AIDS prevention efforts linked to the tournament include: radio and television AIDS prevention spots featuring famous football players; campaign orientation and training in AIDS outreach and education for coaches and team managers; telephone hotlines for HIV/AIDS counseling through public phone booths and health information booths; AIDS information caravans to support community awareness rallies about AIDS prevention; and a minute of silence at the beginning of all matches to commemorate soccer heroes and other loved ones who have died of AIDS.

  17. Homology-dependent Gene Silencing in Paramecium

    Science.gov (United States)

    Ruiz, Françoise; Vayssié, Laurence; Klotz, Catherine; Sperling, Linda; Madeddu, Luisa

    1998-01-01

    Microinjection at high copy number of plasmids containing only the coding region of a gene into the Paramecium somatic macronucleus led to a marked reduction in the expression of the corresponding endogenous gene(s). The silencing effect, which is stably maintained throughout vegetative growth, has been observed for all Paramecium genes examined so far: a single-copy gene (ND7), as well as members of multigene families (centrin genes and trichocyst matrix protein genes) in which all closely related paralogous genes appeared to be affected. This phenomenon may be related to posttranscriptional gene silencing in transgenic plants and quelling in Neurospora and allows the efficient creation of specific mutant phenotypes thus providing a potentially powerful tool to study gene function in Paramecium. For the two multigene families that encode proteins that coassemble to build up complex subcellular structures the analysis presented herein provides the first experimental evidence that the members of these gene families are not functionally redundant. PMID:9529389

  18. What is the clinical significance of ventricular mural antagonism?

    DEFF Research Database (Denmark)

    Lunkenheimer, Paul P; Niederer, Peter; Stephenson, Robert S

    2018-01-01

    for the existence of such forces, which are auxotonic in nature. This is in contrast to the tangentially aligned myocytes that produce constrictive forces, which are unloading in nature. The ventricular myocardium is, therefore, able to function in an antagonistic fashion, with the prevailing constrictive forces...... acting simultaneously with a dilatory force component. The ratio of constrictive to dilating force varies locally according to the specific mural architecture. Such antagonism acts according to local demands to preserve the ventricular shape, store the elastic energy that drives the fast late systolic...

  19. Platformed antagonism: Racist discourses on fake Muslim Facebook pages

    DEFF Research Database (Denmark)

    Farkas, Johan; Schou, Jannick; Neumayer, Christina

    2018-01-01

    This research examines how fake identities on social media create and sustain antagonistic and racist discourses. It does so by analysing 11 Danish Facebook pages, disguised as Muslim extremists living in Denmark, conspiring to kill and rape Danish citizens. It explores how anonymous content...... producers utilize Facebook's socio-technical characteristics to construct, what we propose to term as, platformed antagonism. This term refers to socio-technical and discursive practices that produce new modes of antagonistic relations on social media platforms. Through a discourse-theoretical analysis...

  20. Molecular chaperones antagonize proteotoxicity by differentially modulating protein aggregation pathways.

    Science.gov (United States)

    Douglas, Peter M; Summers, Daniel W; Cyr, Douglas M

    2009-01-01

    The self-association of misfolded or damaged proteins into ordered amyloid-like aggregates characterizes numerous neurodegenerative disorders. Insoluble amyloid plaques are diagnostic of many disease states. Yet soluble, oligomeric intermediates in the aggregation pathway appear to represent the toxic culprit. Molecular chaperones regulate the fate of misfolded proteins and thereby influence their aggregation state. Chaperones conventionally antagonize aggregation of misfolded, disease proteins and assist in refolding or degradation pathways. Recent work suggests that chaperones may also suppress neurotoxicity by converting toxic, soluble oligomers into benign aggregates. Chaperones can therefore suppress or promote aggregation of disease proteins to ameliorate the proteotoxic accumulation of soluble, assembly intermediates.

  1. Building a new research framework for social evolution: intralocus caste antagonism.

    Science.gov (United States)

    Pennell, Tanya M; Holman, Luke; Morrow, Edward H; Field, Jeremy

    2018-01-16

    The breeding and non-breeding 'castes' of eusocial insects provide a striking example of role-specific selection, where each caste maximises fitness through different morphological, behavioural and physiological trait values. Typically, queens are long-lived egg-layers, while workers are short-lived, largely sterile foragers. Remarkably, the two castes are nevertheless produced by the same genome. The existence of inter-caste genetic correlations is a neglected consequence of this shared genome, potentially hindering the evolution of caste dimorphism: alleles that increase the productivity of queens may decrease the productivity of workers and vice versa, such that each caste is prevented from reaching optimal trait values. A likely consequence of this 'intralocus caste antagonism' should be the maintenance of genetic variation for fitness and maladaptation within castes (termed 'caste load'), analogous to the result of intralocus sexual antagonism. The aim of this review is to create a research framework for understanding caste antagonism, drawing in part upon conceptual similarities with sexual antagonism. By reviewing both the social insect and sexual antagonism literature, we highlight the current empirical evidence for caste antagonism, discuss social systems of interest, how antagonism might be resolved, and challenges for future research. We also introduce the idea that sexual and caste antagonism could interact, creating a three-way antagonism over gene expression. This includes unpacking the implications of haplodiploidy for the outcome of this complex interaction. © 2018 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.

  2. Gas turbine exhaust system silencing design

    International Nuclear Information System (INIS)

    Ozgur, D.

    1991-01-01

    Gas turbines are the preferred prime mover in many applications because of their high efficiency, fuel flexibility, and low environmental impact. A typical mid-size machine might have a power rating of 80 MW, a flow of about 1000 kg/hr, and an exhaust temperature of over 500C. The most powerful single source of noise is generally the exhaust, which may generate over a kilowatt of acoustic energy. This paper reports that there are two important ways in which exhaust systems can radiate noise. The first is through the discharge of the exhaust duct, with the exhaust gas. Because of the large quantity of hot gas, the duct exit is always oriented vertically; it may be fairly high in the air in order to promote dispersion of the exhaust plume. This source is almost always attenuated by means of a silencer located somewhere in the ductwork. The second source of noise is often called breakout; it is the radiation of exhaust noise through the walls of the ducting. Breakout is most important for those sections of the exhaust duct which lie upstream of the silencer, where sound levels inside the ducting are highest. Both exhaust duct exit noise and breakout noise can be calculated from the sound power level of the gas turbine exhaust and the sound transmission loss (TL) of the silencer and ducting

  3. Antagonism between Bacteriostatic and Bactericidal Antibiotics Is Prevalent

    Science.gov (United States)

    Lázár, Viktória; Papp, Balázs; Arnoldini, Markus; Abel zur Wiesch, Pia; Busa-Fekete, Róbert; Fekete, Gergely; Pál, Csaba; Ackermann, Martin; Bonhoeffer, Sebastian

    2014-01-01

    Combination therapy is rarely used to counter the evolution of resistance in bacterial infections. Expansion of the use of combination therapy requires knowledge of how drugs interact at inhibitory concentrations. More than 50 years ago, it was noted that, if bactericidal drugs are most potent with actively dividing cells, then the inhibition of growth induced by a bacteriostatic drug should result in an overall reduction of efficacy when the drug is used in combination with a bactericidal drug. Our goal here was to investigate this hypothesis systematically. We first constructed time-kill curves using five different antibiotics at clinically relevant concentrations, and we observed antagonism between bactericidal and bacteriostatic drugs. We extended our investigation by performing a screen of pairwise combinations of 21 different antibiotics at subinhibitory concentrations, and we found that strong antagonistic interactions were enriched significantly among combinations of bacteriostatic and bactericidal drugs. Finally, since our hypothesis relies on phenotypic effects produced by different drug classes, we recreated these experiments in a microfluidic device and performed time-lapse microscopy to directly observe and quantify the growth and division of individual cells with controlled antibiotic concentrations. While our single-cell observations supported the antagonism between bacteriostatic and bactericidal drugs, they revealed an unexpected variety of cellular responses to antagonistic drug combinations, suggesting that multiple mechanisms underlie the interactions. PMID:24867991

  4. Chronicles of Insurrection: Tronti, Negri and the Subject of Antagonism

    Directory of Open Access Journals (Sweden)

    Alberto Toscano

    2009-05-01

    Full Text Available This article seeks to trace the origins of contemporary ‘post-workerism’ in the formulation of concepts of political subjectivity, antagonism and insurrection in Tronti and Negri. In particular, it tries to excavate the seemingly paradoxical position which postulates the increasing immanence of struggles, as based on the Marxian thesis of real subsumption, together with the intensification of the political autonomy or separation of the working class. In order to grasp the political and theoretical proposals of Italian workerism and autonomism, Toscano concentrates on the thesis of a historical transformation of capitalism into an increasingly parasitical and politically violent social relation, a thesis which is grounded in an interpretation of Marx’s notion of ‘tendency’ and which serves as the background to the exploration, especially in Negri, of increasingly uncompromising forms of antagonism. The article focuses especially on Tronti’s so-called ‘Copernican revolution’—giving workers’ struggles primacy in the understanding of capitalism—and critically inquires into the effect of this workerist axiom on Negri’s writings on proletarian sabotage and insurrection in the 1970s. By way of a conclusion, it notes the difficulties in prolonging the workerist gambit in light of capital’s continued effort, as Tronti would put it, to emancipate itself from the working class.

  5. Antagonism trait facets and comprehensive psychosocial disability: Comparing information across self, informant, and interviewer reports.

    Science.gov (United States)

    Ro, Eunyoe; Nuzum, Hallie; Clark, Lee Anna

    2017-10-01

    It is widely known that personality traits collectively discussed as the Dark Triad are antagonistic and associated with poor interpersonal relationships, but few studies have examined how specific facets of antagonism are associated with psychosocial adjustment or how antagonism relates to psychosocial adjustment other than interpersonal functioning. The purpose of this study was to examine how 6 antagonism facets-manipulativeness, grandiosity, attention-seeking, hostility, callousness, and deceitfulness-relate to comprehensive psychosocial functional domains (i.e., well-being, interpersonal relationships, basic daily functioning) using information about both antagonism and functioning from 3 sources-self, informant, and interviewer. Data were from 318 primary participants and informants. We present 3 main findings: (1) When psychosocial functioning and antagonism traits were both rated by informants, all psychosocial disability domains were consistently positively associated with antagonism traits. (2) We next created a single psychosocial-disability factor score via principal factors analysis of all raters' psychosocial-functioning scores. When all 3 raters' reports of domain-level antagonism were used as independent variables in a simultaneous regression analysis to predict this overall functioning score, informant-reported antagonism most strongly predicted psychosocial functioning, followed by interviewer-rated antagonism. (3) We then created 6 facet scores by summing the 3 raters' scores on each. When we used these scores to predict psychosocial functioning, hostility was the main trait significantly predicting psychosocial functioning. The study provides further insight into associations of psychosocial disability with antagonism facets from different raters' perspectives. The findings thus further our understanding of psychosocial outcomes associated with antagonism, the core of the dark traits. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  6. WIF1 is a frequent target for epigenetic silencing in squamous cell carcinoma of the cervix.

    Science.gov (United States)

    Delmas, Amber L; Riggs, Bridget M; Pardo, Carolina E; Dyer, Lisa M; Darst, Russell P; Izumchenko, Eugene G; Monroe, Mänette; Hakam, Ardeshir; Kladde, Michael P; Siegel, Erin M; Brown, Kevin D

    2011-11-01

    Aberrant activation of the Wnt/β-catenin signaling axis is a prominent oncogenic mechanism in numerous cancers including cervical cancer. Wnt inhibitory factor-1 (WIF1) is a secreted protein that binds Wnt and antagonizes Wnt activity. While the WIF1 gene is characterized as a target for epigenetic silencing in some tumor types, WIF1 expression has not been examined in human cervical tissue and cervical cancer. Here, we show that WIF1 is unmethylated and its gene product is expressed in normal cervical epithelium and some cultured cervical tumor lines. In contrast, several cervical cancer lines contained dense CpG methylation within the WIF1 gene, and expression of both WIF1 transcript and protein was restored by culturing cells in the presence of the global DNA demethylating agent 5-aza-2'-deoxycytidine. Using single-molecule MAPit methylation footprinting, we observed differences in chromatin structure within the WIF1 promoter region between cell lines that express and those that do not express WIF1, consistent with transcriptional activity and repression, respectively. The WIF1 promoter was aberrantly methylated in ∼60% (10 of 17) high-grade highly undifferentiated squamous cell cervical tumors examined, whereas paired normal tissue showed significantly lower levels of CpG methylation. WIF1 protein was not detectable by immunohistochemistry in tumors with quantitatively high levels of WIF1 methylation. Of note, WIF1 protein was not detectable in two of the seven unmethylated cervical tumors examined, suggesting other mechanisms may contribute WIF1 repression. Our findings establish the WIF1 gene as a frequent target for epigenetic silencing in squamous cell carcinoma of the cervix.

  7. Veiled Word(s) – Sacred Silence

    DEFF Research Database (Denmark)

    Isar, Nicoletta

    2014-01-01

    This paper defines the Byzantine altar as a sacred space of participative performance in the mystery of the Eucharist – a paradigm of “timeless re-enactment of the Christian drama.” Reading a series of Byzantine ekphraseis, the paper addresses such concepts as inner vision (theoria), silent...... or secret prayer, and divine silence, which are at the very centre of the Byzantine altar. The main focus is to investigate the liminal nature of the Mystery, manifested through concealing-revealing devices, which are thresholds in the liturgical participation of the Byzantine subject. Fear and secrecy...

  8. Therapeutic potential of endothelin receptor antagonism in kidney disease.

    Science.gov (United States)

    Czopek, Alicja; Moorhouse, Rebecca; Webb, David J; Dhaun, Neeraj

    2016-03-01

    Our growing understanding of the role of the endothelin (ET) system in renal physiology and pathophysiology is from emerging studies of renal disease in animal models and humans. ET receptor antagonists reduce blood pressure and proteinuria in chronic kidney disease and cause regression of renal injury in animals. However, the therapeutic potential of ET receptor antagonism has not been fully explored and clinical studies have been largely limited to patients with diabetic nephropathy. There remains a need for more work in nondiabetic chronic kidney disease, end-stage renal disease (patients requiring maintenance dialysis and those with a functioning kidney transplant), ischemia reperfusion injury, and sickle cell disease. The current review summarizes the most recent advances in both preclinical and clinical studies of ET receptor antagonists in the field of kidney disease. Copyright © 2016 the American Physiological Society.

  9. Selective and mixed endothelin receptor antagonism in cardiovascular disease.

    Science.gov (United States)

    Dhaun, Neeraj; Pollock, David M; Goddard, Jane; Webb, David J

    2007-11-01

    Within five years of discovering endothelin (ET-1) in 1988, the first report of an orally available ET receptor antagonist was published. Within twelve years, bosentan, the first ET receptor antagonist to gain marketing authorization, was made available for the treatment of pulmonary artery hypertension (PAH). Since this milestone in ET biology, several ET receptor antagonists have been developed, principally to target cardiovascular disease states. ET-1 acts through two receptors--ET(A) and ET(B). Currently, the mixed antagonist, bosentan, and the selective ET(A) antagonist, sitaxsentan, are both licensed for the treatment of PAH, and clinical trials with these and other agents are ongoing for many diseases, including scleroderma, diabetic nephropathy and prostate cancer. Although there has been no argument about the importance of blocking ET(A) receptors, there remains a long-running debate as to whether additional ET(B) antagonism is of benefit, and this is the topic of the following review.

  10. Calcitonin gene-related peptide antagonism and cluster headache

    DEFF Research Database (Denmark)

    Ashina, Håkan; Newman, Lawrence; Ashina, Sait

    2017-01-01

    Calcitonin gene-related peptide (CGRP) is a key signaling molecule involved in migraine pathophysiology. Efficacy of CGRP monoclonal antibodies and antagonists in migraine treatment has fueled an increasing interest in the prospect of treating cluster headache (CH) with CGRP antagonism. The exact...... role of CGRP and its mechanism of action in CH have not been fully clarified. A search for original studies and randomized controlled trials (RCTs) published in English was performed in PubMed and in ClinicalTrials.gov . The search term used was "cluster headache and calcitonin gene related peptide......" and "primary headaches and calcitonin gene related peptide." Reference lists of identified articles were also searched for additional relevant papers. Human experimental studies have reported elevated plasma CGRP levels during both spontaneous and glyceryl trinitrate-induced cluster attacks. CGRP may play...

  11. Interferon Induction by RNA Viruses and Antagonism by Viral Pathogens

    Directory of Open Access Journals (Sweden)

    Yuchen Nan

    2014-12-01

    Full Text Available Interferons are a group of small proteins that play key roles in host antiviral innate immunity. Their induction mainly relies on host pattern recognition receptors (PRR. Host PRR for RNA viruses include Toll-like receptors (TLR and retinoic acid-inducible gene I (RIG-I like receptors (RLR. Activation of both TLR and RLR pathways can eventually lead to the secretion of type I IFNs, which can modulate both innate and adaptive immune responses against viral pathogens. Because of the important roles of interferons, viruses have evolved multiple strategies to evade host TLR and RLR mediated signaling. This review focuses on the mechanisms of interferon induction and antagonism of the antiviral strategy by RNA viruses.

  12. Arsenic silences hepatic PDK4 expression through activation of histone H3K9 methylatransferase G9a

    International Nuclear Information System (INIS)

    Zhang, Xi; Wu, Jianguo; Choiniere, Jonathan; Yang, Zhihong; Huang, Yi; Bennett, Jason; Wang, Li

    2016-01-01

    It is well established that increased liver cancer incidence is strongly associated with epigenetic silencing of tumor suppressor genes; the latter is contributed by the environmental exposure to arsenic. Pyruvate dehydrogenase kinase 4 (PDK4) is a mitochondrial protein that regulates the TCA cycle. However, the epigenetic mechanisms mediated by arsenic to control PDK4 expression remain elusive. In the present study, we showed that histone methyltransferase G9a- and Suv39H-mediated histone H3 lysine 9 (H3K9) methylations contributed to PDK4 silencing in hepatic cells. The PDK4 expression was induced by G9a inhibitor BRD4770 (BRD) and Suv39H inhibitor Chaetocin (CHA). In contrast, arsenic exposure decreased PDK4 expression by inducing G9a and increasing H3K9 di- and tri-methylations levels (H3K9me2/3). In addition, arsenic exposure antagonizes the effect of BRD by enhancing the enrichment of H3K9me2/3 in the PKD4 promoter. Moreover, knockdown of G9a using siRNA induced PDK4 expression in HCC cells. Furthermore, arsenic decreased hepatic PDK4 expression as well as diminished the induction of PDK4 by BRD in mouse liver and hepatocytes. Overall, the results suggest that arsenic causes aberrant repressive histone modification to silence PDK4 in both HCC cells and in mouse liver. - Graphical abstract: Schematic showing arsenic-mediated epigenetic pathway that inhibits PDK4 expression. (A) BRD induces PDK4 expression by decreasing G9a protein and histone H3K9me2 and H3K9me3 levels as well as diminishing their recruitment to the PDK4 promoter. (B) Arsenic counteracts the effect of BRD by increasing histone H3K9me2 and H3K9me3 levels as well as enhancing their enrichment to the PDK4 promoter. Display Omitted - Highlights: • Histone methyltrasferase G9a inhibitor BRD induces PDK4 expression. • Arsenic decreases PDK4 expression and increases H3K9me2 and me3 levels. • Arsenic enhances H3K9me2/me3 enrichment in the PDK4 promoter. • Arsenic antagonizes the activation of

  13. Collaborative silence and some unguided prerogative utterances of ...

    African Journals Online (AJOL)

    This essay attempts to demystify the silence and non-prosecution syndrome surrounding unguided prerogative utterances of Nigerian leaders as a contemporary culture, which has continued to threaten the unity and stability of the country. In doing this, the silence and withdrawal of key Nigerian agencies, such as; the ...

  14. Echoes of Silence: Empathy and Making Connections through Writing Process

    Science.gov (United States)

    Freedman, Joel M.

    2009-01-01

    On April 25, 2008, students on college and public school campuses collectively committed to a vow of silence commemorating an event known as the National Day of Silence. This student-generated, nationwide action theatrically "speaks out" in solidarity with lesbian, gay, bisexual, and transgender (LGBT) people who for one reason or another fear…

  15. The Educators' Guide to the Day of Silence

    Science.gov (United States)

    Gay, Lesbian and Straight Education Network (GLSEN), 2010

    2010-01-01

    The Day of Silence is the largest single student-led action towards creating safer schools for all, regardless of sexual orientation, gender identity or gender expression. From the first-ever Day of Silence at the University of Virginia in 1996, to the organizing efforts in over 8,000 middle schools, high schools, colleges and universities across…

  16. Reflections on the Silencing the Self Scale and Its Origins

    Science.gov (United States)

    Jack, Dana Crowley

    2011-01-01

    In this article, the author reflects on the Silencing the Self Scale (STSS) and blends her personal and professional thoughts about self-silencing, gender, and depression. For her, the despair of depression deeply involves questions of value and meaning, culture and freedom. The STSS grew from listening to depressed women's voices. From them, the…

  17. Antiviral RNA silencing viral counter defense in plants

    NARCIS (Netherlands)

    Bucher, E.C.

    2006-01-01

    The research described in this thesis centres around the mechanism of RNA silencing in relation to virus-host interaction, an area of increasing importance. It shows how this recently disclosed mechanism can be used to produce virus-resistant plants. Based on the activity of the RNA silencing

  18. Language and silence: persoonlike herinneringe aan Adam Small ...

    African Journals Online (AJOL)

    Owner

    En hy was self nooit kategories of dogmaties in sy denke of uitsprake nie. Die titel van my voordrag is “Language and silence: persoonlike herinneringe aan. 'n digter-intellektueel”. Dis Adam wat my as student voorgestel het aan George Steiner se “Language and Silence: Essays on Language, Literature and the Inhumane.

  19. Strategic Silence as a Tool of Political Communication: A Reflection ...

    African Journals Online (AJOL)

    The paper, therefore, recommended that politicians should be cautious in the use of strategic silence as a means of political communication in view of the nature of politics which calls for self- expression in the use of persuasion, clarification and conviction to win public support and sympathy. Maintaining silence when one is ...

  20. No-Big-Silence teeb klubituuri / Urmas Hännile

    Index Scriptorium Estoniae

    Hännile, Urmas

    2009-01-01

    Rockansamblist No-Big-Silence ja dark-popansamblist Sinine, nende kontsertttuurist mööda Eestimaad, tutvustamisel bändide uued albumid (No-Big-Silence "Starstealer" ja Sinine "Butterflies"), Pärnus on kontsert 24. oktoobril klubis Sugar

  1. The evolution of reduced antagonism--A role for host-parasite coevolution.

    Science.gov (United States)

    Gibson, A K; Stoy, K S; Gelarden, I A; Penley, M J; Lively, C M; Morran, L T

    2015-11-01

    Why do some host-parasite interactions become less antagonistic over evolutionary time? Vertical transmission can select for reduced antagonism. Vertical transmission also promotes coevolution between hosts and parasites. Therefore, we hypothesized that coevolution itself may underlie transitions to reduced antagonism. To test the coevolution hypothesis, we selected for reduced antagonism between the host Caenorhabditis elegans and its parasite Serratia marcescens. This parasite is horizontally transmitted, which allowed us to study coevolution independently of vertical transmission. After 20 generations, we observed a response to selection when coevolution was possible: reduced antagonism evolved in the copassaged treatment. Reduced antagonism, however, did not evolve when hosts or parasites were independently selected without coevolution. In addition, we found strong local adaptation for reduced antagonism between replicate host/parasite lines in the copassaged treatment. Taken together, these results strongly suggest that coevolution was critical to the rapid evolution of reduced antagonism. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  2. Chinanteco children’s silences in different classroom situations

    Directory of Open Access Journals (Sweden)

    Valeria Rebolledo Angulo

    2016-01-01

    Full Text Available This article analyzes, from an ethnographic perspective and a sociocultural framework, the construction of silences in the interaction between students and teachers in a multilingual classroom situation in an indigenous community in méxico. the analysis reveals how the silence of the chinanteco speaking children when asked to answer certain questions in class is not always due to their failure to understand spoken and written spanish that is used in class. their silences are responses taking different meanings in specific situations. the silence of the children can be a way of resisting, a way of hiding, and, sometimes, their voices are silenced.

  3. The RNA silencing pathway: the bits and pieces that matter.

    Directory of Open Access Journals (Sweden)

    Marian A C Groenenboom

    2005-07-01

    Full Text Available Cellular pathways are generally proposed on the basis of available experimental knowledge. The proposed pathways, however, may be inadequate to describe the phenomena they are supposed to explain. For instance, by means of concise mathematical models we are able to reveal shortcomings in the current description of the pathway of RNA silencing. The silencing pathway operates by cleaving siRNAs from dsRNA. siRNAs can associate with RISC, leading to the degradation of the target mRNA. We propose and analyze a few small extensions to the pathway: a siRNA degrading RNase, primed amplification of aberrant RNA pieces, and cooperation between aberrant RNA to trigger amplification. These extensions allow for a consistent explanation for various types of silencing phenomena, such as virus induced silencing, transgene and transposon induced silencing, and avoidance of self-reactivity, as well as for differences found between species groups.

  4. Dynamics of Chromatin Silencing at Telomeres: Deterministic and Stochastic Aspects

    Science.gov (United States)

    Apratim, Manjul; Dayarian, Adel; Sontag, Eduardo; Sengupta, Anirvan

    2012-02-01

    Epigenetic silencing modifications of are often associated with well-defined domains. We study potential mechanisms of formation of boundary of silenced regions. We specially focus on the possibility that some telomeric silencing boundaries are formed in a self-organized manner, as opposed to being defined by specific boundary elements. In particular, we examine systems where a titration-induced feedback can stabilize the boundary of the silenced region. A consequence of having multiple such boundaries is large stochastic cell-to-cell variation of boundary locations. We proceed to make an argument about the nature of the fall-off of the average silencing protein occupancy, coming from such variability, and test the predictions against HA-Sir3 ChIP-seq data from experiments performed on yeast.

  5. The Curious Silence of the Dog and Paul of Tarsus; Revisiting The Argument from Silence

    Directory of Open Access Journals (Sweden)

    Michael Gary Duncan

    2012-03-01

    Full Text Available In this essay I propose an interpretative and explanatory structure for the so-called argumentum ex silento, or argument from silence (henceforth referred to as the AFS. To this end, I explore two examples, namely, Sherlock Holmes’s oft-quoted notice of the “curious incident of the dog in the night-time” from Arthur Conan Doyle’s short story “Silver Blaze,” and the historical question of Paul of Tarsus’s silence on biographical details of the historical Jesus. Through these cases, I conclude that the AFS serves as a dialogical topos best evaluated and understood through the perceived authority of the arguer and the willingness of the audience to accept that authority, due to the “curious” nature of the negative evidence that the argument employed.

  6. The ethics of silence: Does conflict of interest explain employee silence?

    Science.gov (United States)

    Anderson, James

    2018-03-01

    Employee silence constitutes a significant threat to organizational success. This article argues that silence is a by-product of a structural Conflict of Interest (COI) between employees and their employers. This argument turns on the claim, also defended here, that employees are in a privileged position vis-à-vis knowledge of their work and that leaders-whether they recognize it or not-are dependent on their employees for reliable information about the work they are doing. Employee voice, therefore, is an organizational necessity. It is also a moral achievement as it involves risking one's personal interests for the sake of the organization. Leaders must take steps to mitigate COI and encourage employee voice; this article provides several strategies for doing exactly that.

  7. Viral counterdefense on RNA silencing : analysis of RNA silencing suppressors from arthropod-borne negative strand RNA plant viruses

    NARCIS (Netherlands)

    Schnettler, E.

    2010-01-01

    This thesis describes that RNA silencing suppressor (RSS) proteins encoded by negative-stranded RNA plant viruses are able to interfere with different RNA silencing pathways in a variety of organisms by interacting with double stranded (ds)RNA molecules. These RSS proteins are able to counteract the

  8. Virus-induced gene silencing in diverse maize lines using the Brome Mosaic virus-based silencing vector

    Science.gov (United States)

    Virus-induced gene silencing (VIGS) is a widely used tool for gene function studies in many plant species, though its use in monocots has been limited. Using a Brome mosaic virus (BMV) vector designed to silence the maize phytoene desaturase gene, a genetically diverse set of maize inbred lines was ...

  9. Caffeine antagonism of alcohol-induced driving impairment.

    Science.gov (United States)

    Liguori, A; Robinson, J H

    2001-07-01

    The extent to which caffeine antagonizes alcohol-induced impairment of simulated automobile driving at the current lowest legal American limit (0.08% BrAC) was the focus of this study. Fifteen adults swallowed a capsule (0, 200, or 400 mg caffeine) then drank a beverage (0.0 or 0.6 g/kg ethanol) in a within-subject, double-blind, randomized procedure. Forty-five minutes later, participants completed a test battery of subjective effects scales, dynamic posturography, critical flicker fusion (CFF), choice reaction time (CRT), divided attention (Stroop test), and simulated driving. Alcohol alone increased ratings of 'dizzy', 'drug effect', and 'high', slowed CRT and brake latency, and increased body sway. Caffeine alone increased ratings of 'alert' and 'jittery', but did not significantly affect body sway or psychomotor performance. Both caffeine doses comparably counteracted alcohol impairment of brake latency but not CRT or body sway. Brake latency with either alcohol-caffeine combination remained significantly longer than that with placebo. Stroop and CFF performance were unaffected by any drug condition. The results suggest that caffeine may increase alertness and improve reaction time after alcohol use but will not completely counteract alcohol impairment in a driver.

  10. Superiority of antagonic-stress composition versus nicergoline in gerontopsychiatry.

    Science.gov (United States)

    Schneider, F; Popa, R; Mihalas, G; Stefanigă, P; Mihalas, I G; Măties, R; Mateescu, R

    1994-06-30

    Nicergoline (NE)--a cerebral vasodilator with nicotinic acid esterified in its molecule--and Antagonic-Stress (AS) composition--a neurometabolic nootropic, also containing nicotinic acid but with fast and prolonged release--were evaluated in senile dementia of Alzheimer's type (SDAT), mild to moderate intensity (DSM-IV Options Book, 1991 and ICD-10, 1990 criteria). A double-blind, randomized, comparative, and parallel clinical trial was performed on 62 old people divided into 2 groups and exclusively treated with NE or AS. Psychogeriatric evaluations (Sandoz Clinical Assessment-Geriatric scale, Self-Assessment Scale-Geriatric and their subscales) and psychometric tests (digit symbol of WAIS, Wechsler Memory Scale, and Wechsler Adult Intelligence Scale-WAIS) were made before and after 3 months of treatment. Prolonged and large dose treatments with NE and AS significantly decreased the psychogeriatric scores, diminished the deterioration index, and improved cognitive performances (ANOVA). Therapeutical effects of AS were significantly higher than those of NE (ANCOVA). The better actions of AS in senile dementia and for improving cognitive function and behavior are discussed in connection with its multiple neurometabolic composition, the synergism of components, the antiischemic action of its antioxidants, its anti-free radical complementary action (deceleration of the aging rate, brain and erythrocyte lipofuscinolysis, complex antioxidative and scavenger formula), the multivitamin and multimineral supplementation and, finally, with the superiority of multitherapy vs. monotherapy.

  11. Tachykinin receptors antagonism for asthma: a systematic review

    Directory of Open Access Journals (Sweden)

    Couto Nuno

    2011-08-01

    Full Text Available Abstract Background Tachykinins substance P, neurokinin A and neurokinin B seem to account for asthma pathophysiology by mediating neurogenic inflammation and several aspects of lung mechanics. These neuropeptides act mainly by their receptors NK1, NK2 and NK3, respectively which may be targets for new asthma therapy. Methods This review systematically examines randomized controlled trials evaluating the effect of tachykinins receptors antagonism on asthma. Symptoms, airway inflammation, lung function and airway inflammation were considered as outcomes. We searched the Cochrane Airways Group Specialized Register of Asthma Trials, Cochrane Database of Systematic Reviews, MEDLINE/PubMed and EMBASE. The search is as current as June 2010. Quality rating of included studies followed the Cochrane Collaboration and GRADE Profiler approaches. However, data were not pooled together due to different measures among the studies. Results Our systematic review showed the potential of NK receptor antagonist to decrease airway responsiveness and to improve lung function. However, effects on airway inflammation and asthma symptoms were poorly or not described. Conclusion The limited available evidence suggests that tachykinin receptors antagonists may decrease airway responsiveness and improve lung function in patients with asthma. Further large randomized trials are still required.

  12. Bioinformatics tools for achieving better gene silencing in plants.

    Science.gov (United States)

    Ahmed, Firoz; Dai, Xinbin; Zhao, Patrick Xuechun

    2015-01-01

    RNA interference (RNAi) is one of the most popular and effective molecular technologies for knocking down the expression of an individual gene of interest in living organisms. Yet the technology still faces the major issue of nonspecific gene silencing, which can compromise gene functional characterization and the interpretation of phenotypes associated with individual gene knockdown. Designing an effective and target-specific small interfering RNA (siRNA) for induction of RNAi is therefore the major challenge in RNAi-based gene silencing. A 'good' siRNA molecule must possess three key features: (a) the ability to specifically silence an individual gene of interest, (b) little or no effect on the expressions of unintended siRNA gene targets (off-target genes), and (c) no cell toxicity. Although several siRNA design and analysis algorithms have been developed, only a few of them are specifically focused on gene silencing in plants. Furthermore, current algorithms lack a comprehensive consideration of siRNA specificity, efficacy, and nontoxicity in siRNA design, mainly due to lack of integration of all known rules that govern different steps in the RNAi pathway. In this review, we first describe popular RNAi methods that have been used for gene silencing in plants and their serious limitations regarding gene-silencing potency and specificity. We then present novel, rationale-based strategies in combination with computational and experimental approaches to induce potent, specific, and nontoxic gene silencing in plants.

  13. Antagonism of relaxin by glibenclamide in the uterus of the rat in vivo.

    Science.gov (United States)

    Downing, S J; Hollingsworth, M

    1991-09-01

    1. The effects of glibenclamide (a blocker of adenosine triphosphate [ATP]-dependent K(+)-channels) on the inhibition of uterine contractions by relaxin, salbutamol and cromakalim were compared in vivo. 2. Glibenclamide (20 mg kg-1) did not antagonize salbutamol. Glibenclamide produced a parallel rightward shift in the dose-response curve to cromakalim with a 5.5 fold decrease in uterine sensitivity (post-vehicle log ID50, -0.87 mg kg-1; post-glibenclamide log ID50, -0.07 mg kg-1). Glibenclamide produced a non-parallel rightward shift in the dose-response curve to relaxin (post-vehicle log ID50, 0.99 microgram kg-1; post-glibenclamide log ID50, 2.28 micrograms kg-1). 3. Glibenclamide reversed established inhibition of uterine contractions by cromakalim or relaxin but not that by salbutamol. 4. Insulin produced no antagonism of relaxin on isolated uterus of the rat, demonstrating that glibenclamide antagonism of relaxin in vivo is not by released insulin. Apamin did not antagonize relaxin in vivo, suggesting that small calcium-activated K(+)-channels are not involved in the action of relaxin. 5. Comparison of the lack of antagonism of salbutamol with the non-competitive-like antagonism of relaxin by glibenclamide suggests that relaxin does not relax uterine smooth muscle predominantly by increasing intracellular adenosine 3', 5'-cyclic monophosphate concentrations. Comparison of the non-competitive-like antagonism of relaxin and the competitive-like antagonism of cromakalim by glibenclamide suggests that the two relaxants may share, in part, a common mechanism of action and that additional mechanism(s) may also be involved in the inhibitory action of relaxin.

  14. Autotaxin is induced by TSA through HDAC3 and HDAC7 inhibition and antagonizes the TSA-induced cell apoptosis

    Science.gov (United States)

    2011-01-01

    Background Autotaxin (ATX) is a secreted glycoprotein with the lysophospholipase D (lysoPLD) activity to convert lysophosphatidylcholine (LPC) into lysophosphatidic acid (LPA), a bioactive lysophospholipid involved in diverse biological actions. ATX is highly expressed in some cancer cells and contributes to their tumorigenesis, invasion, and metastases, while in other cancer cells ATX is silenced or expressed at low level. The mechanism of ATX expression regulation in cancer cells remains largely unknown. Results In the present study, we demonstrated that trichostatin A (TSA), a well-known HDAC inhibitor (HDACi), significantly induced ATX expression in SW480 and several other cancer cells with low or undetectable endogenous ATX expression. ATX induction could be observed when HDAC3 and HDAC7 were down-regulated by their siRNAs. It was found that HDAC7 expression levels were low in the cancer cells with high endogenous ATX expression. Exogenous over-expression of HDAC7 inhibited ATX expression in these cells in a HDAC3-dependent manner. These data indicate that HDAC3 and HDAC7 collaboratively suppress ATX expression in cancer cells, and suggest that TSA induce ATX expression by inhibiting HDAC3 and HDAC7. The biological significance of this regulation mechanism was revealed by demonstrating that TSA-induced ATX protected cancer cells against TSA-induced apoptosis by producing LPA through its lysoPLD activity, which could be reversed by BrP-LPA and S32826, the inhibitors of the ATX-LPA axis. Conclusions We have demonstrated that ATX expression is repressed by HDAC3 and HDAC7 in cancer cells. During TSA treatment, ATX is induced due to the HDAC3 and HDAC7 inhibition and functionally antagonizes the TSA-induced apoptosis. These results reveal an internal HDACi-resistant mechanism in cancer cells, and suggest that the inhibition of ATX-LPA axis would be helpful to improve the efficacy of HDACi-based therapeutics against cancer. PMID:21314984

  15. Autotaxin is induced by TSA through HDAC3 and HDAC7 inhibition and antagonizes the TSA-induced cell apoptosis

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    Zhang Junjie

    2011-02-01

    Full Text Available Abstract Background Autotaxin (ATX is a secreted glycoprotein with the lysophospholipase D (lysoPLD activity to convert lysophosphatidylcholine (LPC into lysophosphatidic acid (LPA, a bioactive lysophospholipid involved in diverse biological actions. ATX is highly expressed in some cancer cells and contributes to their tumorigenesis, invasion, and metastases, while in other cancer cells ATX is silenced or expressed at low level. The mechanism of ATX expression regulation in cancer cells remains largely unknown. Results In the present study, we demonstrated that trichostatin A (TSA, a well-known HDAC inhibitor (HDACi, significantly induced ATX expression in SW480 and several other cancer cells with low or undetectable endogenous ATX expression. ATX induction could be observed when HDAC3 and HDAC7 were down-regulated by their siRNAs. It was found that HDAC7 expression levels were low in the cancer cells with high endogenous ATX expression. Exogenous over-expression of HDAC7 inhibited ATX expression in these cells in a HDAC3-dependent manner. These data indicate that HDAC3 and HDAC7 collaboratively suppress ATX expression in cancer cells, and suggest that TSA induce ATX expression by inhibiting HDAC3 and HDAC7. The biological significance of this regulation mechanism was revealed by demonstrating that TSA-induced ATX protected cancer cells against TSA-induced apoptosis by producing LPA through its lysoPLD activity, which could be reversed by BrP-LPA and S32826, the inhibitors of the ATX-LPA axis. Conclusions We have demonstrated that ATX expression is repressed by HDAC3 and HDAC7 in cancer cells. During TSA treatment, ATX is induced due to the HDAC3 and HDAC7 inhibition and functionally antagonizes the TSA-induced apoptosis. These results reveal an internal HDACi-resistant mechanism in cancer cells, and suggest that the inhibition of ATX-LPA axis would be helpful to improve the efficacy of HDACi-based therapeutics against cancer.

  16. Transcriptional silencing of multiple genes in trophozoites of Entamoeba histolytica.

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    Rivka Bracha

    2006-05-01

    Full Text Available In a previous work we described the transcriptional silencing of the amoebapore A (AP-A gene (Ehap-a of Entamoeba histolytica strain HM-1:IMSS. The silencing occurred following transfection with a plasmid containing a 5' upstream region (473 bp of Ehap-a that included a truncated segment (140 bp of a short interspersed nuclear element (SINE1. Silencing remained in effect even after removal of the plasmid (clone G3. Neither short interfering RNA nor methylated DNA were detected, but the chromatin domain of Ehap-a in the gene-silenced trophozoites was modified. Two other similar genes (Ehap-b and one encoding a Saposin-like protein, SAPLIP 1 also became silenced. In the present work we demonstrate the silencing of a second gene of choice, one that encodes the light subunit of the Gal/GalNAc inhibitable lectin (Ehlgl1 and the other, the cysteine proteinase 5 (EhCP-5. This silencing occurred in G3 trophozoites transfected with a plasmid in which the 473 bp 5' upstream Ehap-a fragment was directly ligated to the second gene. Transcriptional silencing occurred in both the transgene and the chromosomal gene. SINE1 sequences were essential, as was a direct connection between the Ehap-a upstream region and the beginning of the open reading frame of the second gene. Gene silencing did not occur in strain HM-1:IMSS with any of these plasmid constructs. The trophozoites with two silenced genes were virulence-attenuated as were those of clone G3. In addition, trophozoites not expressing Lgl1 and AP-A proteins had a significantly reduced ability to cap the Gal/GalNAc-lectin to the uroid region when incubated with antibodies against the heavy (170 kDa subunit of the lectin. Lysates of trophozoites lacking cysteine proteinase 5 and AP-A proteins had 30% less cysteine proteinase activity than those of HM-1:IMSS strain or the G3 clone. Silencing of other genes in G3 amoebae could provide a model to study their various functions. In addition, double gene-silenced

  17. Oriana: the voice and the silences

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    Mercedes Rosúa

    2007-09-01

    Full Text Available Commentators did their best to bury the late Oriana Fallaci’s ideas and books written since the 11 S under tons of praises to her previous works, and under deep silence or global discrediting her denunciation of Islamic fundamentalism and of terrorist blackmail and all its forms of getting a grip on Europe. Obituary notices avoided carefully the analysis of facts and data brought forward by Oriana in her three last books: The rage and the pride. The power of the reason and Oriana Fallaci’s inter- view with herself. The Apocalypse. But the italian journalist, who past away on 15th Sep- tember 2006, denounced substantiated facts, true dangers and a real collusion of wes- tern sectors-venal, corrupt, fainthearted and ignorant-with the strategy of penetration and manipulation of public opinion of an islamic movement who is the enemy of democracies, Civil Rights, freedom and the western systems of open society.Key words: Oriana Fallaci, Islamic fundamentalism, Defence freedom, Denun- ciation fear, Europe ́s surrender, Terrorism, Western censorship. 

  18. Breaking the Silence: Feminism and Post humanism

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    Debika Saha

    2015-10-01

    Full Text Available Postmodernism starts its journey by challenging the master narratives of metaphysics and philosophy. In this journey the narrative get replaced either by an emancipation from narratives that claim to possess eternal truth or by a turn to a kind of informative technology. But both the ways keep at their centre the process of “denaturing” or disassociating something of its natural qualities. This postmodernist turn has now taken a new form. The choice is not limited between the natural body and the culturally constructed body, but between different areas of bodily reconstruction bearing different social and cultural implications. As Spivak in her famous writing raises the question «Can the subaltern speak?» In fact, Spivak narrates how the marginalized, the less privileged depend upon the benevolence of the more privileged. To engage with the other means not only to talk, listen, learn or know about her but also to identify with her. There must be some ways for open dialogues that can diminish the effects of cultural dominance. The imperial silence should be broken.

  19. Evidence for gene silencing by endogenous DNA methylation

    Science.gov (United States)

    Holliday, Robin; Ho, Thu

    1998-01-01

    Transformed cells can spontaneously silence genes by de novo methylation, and it is generally assumed that this is due to DNA methyltransferase activity. We have tested the alternative hypothesis that gene silencing could be due to the uptake of 5-methyl-dCMP into DNA, via the di- and triphosphonucleotides. 5-Methyl-dCMP would be present in cells from the ongoing repair of DNA. We have isolated a strain of Chinese hamster ovary (CHO) cells, designated HAM−, which spontaneously silences two tested genes at a very high frequency. We have shown that this strain incorporates 5-[3H]methyldeoxycytidine into 5-methylcytosine and thymine in DNA. It also has low 5-methyl-dCMP deaminase activity. Another HAM+ strain has high deaminase activity and a very low frequency of gene silencing. The starting strain, CHO K1, has a phenotype intermediate between HAM− and HAM+. PMID:9671746

  20. Mutations in Ran system affected telomere silencing in Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Hayashi, Naoyuki; Kobayashi, Masahiko; Shimizu, Hiroko; Yamamoto, Ken-ichi; Murakami, Seishi; Nishimoto, Takeharu

    2007-01-01

    The Ran GTPase system regulates the direction and timing of several cellular events, such as nuclear-cytosolic transport, centrosome formation, and nuclear envelope assembly in telophase. To gain insight into the Ran system's involvement in chromatin formation, we investigated gene silencing at the telomere in several mutants of the budding yeast Saccharomyces cerevisiae, which had defects in genes involved in the Ran system. A mutation of the RanGAP gene, rna1-1, caused reduced silencing at the telomere, and partial disruption of the nuclear Ran binding factor, yrb2-Δ2, increased this silencing. The reduced telomere silencing in rna1-1 cells was suppressed by a high dosage of the SIR3 gene or the SIT4 gene. Furthermore, hyperphosphorylated Sir3 protein accumulated in the rna1-1 mutant. These results suggest that RanGAP is required for the heterochromatin structure at the telomere in budding yeast

  1. Locus-specific ribosomal RNA gene silencing in nucleolar dominance.

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    Michelle S Lewis

    2007-08-01

    Full Text Available The silencing of one parental set of rRNA genes in a genetic hybrid is an epigenetic phenomenon known as nucleolar dominance. We showed previously that silencing is restricted to the nucleolus organizer regions (NORs, the loci where rRNA genes are tandemly arrayed, and does not spread to or from neighboring protein-coding genes. One hypothesis is that nucleolar dominance is the net result of hundreds of silencing events acting one rRNA gene at a time. A prediction of this hypothesis is that rRNA gene silencing should occur independent of chromosomal location. An alternative hypothesis is that the regulatory unit in nucleolar dominance is the NOR, rather than each individual rRNA gene, in which case NOR localization may be essential for rRNA gene silencing. To test these alternative hypotheses, we examined the fates of rRNA transgenes integrated at ectopic locations. The transgenes were accurately transcribed in all independent transgenic Arabidopsis thaliana lines tested, indicating that NOR localization is not required for rRNA gene expression. Upon crossing the transgenic A. thaliana lines as ovule parents with A. lyrata to form F1 hybrids, a new system for the study of nucleolar dominance, the endogenous rRNA genes located within the A. thaliana NORs are silenced. However, rRNA transgenes escaped silencing in multiple independent hybrids. Collectively, our data suggest that rRNA gene activation can occur in a gene-autonomous fashion, independent of chromosomal location, whereas rRNA gene silencing in nucleolar dominance is locus-dependent.

  2. RNA silencing is resistant to low-temperature in grapevine.

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    Marjorie Romon

    Full Text Available RNA silencing is a natural defence mechanism against viruses in plants, and transgenes expressing viral RNA-derived sequences were previously shown to confer silencing-based enhanced resistance against the cognate virus in several species. However, RNA silencing was shown to dysfunction at low temperatures in several species, questioning the relevance of this strategy in perennial plants such as grapevines, which are often exposed to low temperatures during the winter season. Here, we show that inverted-repeat (IR constructs trigger a highly efficient silencing reaction in all somatic tissues in grapevines. Similarly to other plant species, IR-derived siRNAs trigger production of secondary transitive siRNAs. However, and in sharp contrast to other species tested to date where RNA silencing is hindered at low temperature, this process remained active in grapevine cultivated at 4°C. Consistently, siRNA levels remained steady in grapevines cultivated between 26°C and 4°C, whereas they are severely decreased in Arabidopsis grown at 15°C and almost undetectable at 4°C. Altogether, these results demonstrate that RNA silencing operates in grapevine in a conserved manner but is resistant to far lower temperatures than ever described in other species.

  3. Perceived sex discrimination amplifies the effect of antagonism on cigarette smoking.

    Science.gov (United States)

    Sutin, Angelina R; English, Devin; Evans, Michele K; Zonderman, Alan B

    2014-06-01

    Compared to men, the decline in smoking during the past few decades has been slower for women, and smoking-related morbidity and mortality has increased substantially. Identifying sex-specific risk factors will inform more targeted intervention/prevention efforts. The purpose of this research is to examine the interactive effect of psychological (trait antagonism) and social (perceived sex discrimination) factors on current cigarette smoking and whether these effects differ by sex. Participants in the Healthy Aging in Neighborhoods of Diversity across the Life Span study (HANDLS; N = 454) and participants in the Health and Retirement Study (HRS; N = 8,155) completed measures of antagonism, perceived sex discrimination, and reported whether they smoked currently. Logistic regressions were used to predict smoking from antagonism, discrimination, and their interaction. Antagonism was associated with an increased risk of smoking. For women, there was an interaction between antagonism and discrimination: among women who perceived sex discrimination, every standard deviation increase in antagonism was associated with a 2.5 increased risk of current smoking in HANDLS (odds ratio [OR] = 2.54, 95% confidence interval [CI] = 1.46-4.39) and an almost 1.5 increased risk in HRS (OR = 1.43, 95% CI = 1.18-1.73). This interaction was not significant for men in either sample. In 2 independent samples, perceived sex discrimination amplified the effect of antagonism on cigarette smoking for women but not men. A hostile disposition and a perceived hostile social environment have a synergistic effect on current cigarette smoking for women.

  4. Differential effects of ethanol antagonism and neuroprotection in peptide fragment NAPVSIPQ prevention of ethanol-induced developmental toxicity

    OpenAIRE

    Wilkemeyer, Michael F.; Chen, Shao-yu; Menkari, Carrie E.; Brenneman, Douglas E.; Sulik, Kathleen K.; Charness, Michael E.

    2003-01-01

    NAPVSIPQ (NAP), an active fragment of the glial-derived activity-dependent neuroprotective protein, is protective at femtomolar concentrations against a wide array of neural insults and prevents ethanol-induced fetal wastage and growth retardation in mice. NAP also antagonizes ethanol inhibition of L1-mediated cell adhesion (ethanol antagonism). We performed an Ala scanning substitution of NAP to determine the role of ethanol antagonism and neuroprotection in NAP preve...

  5. The Enamovirus P0 protein is a silencing suppressor which inhibits local and systemic RNA silencing through AGO1 degradation

    Energy Technology Data Exchange (ETDEWEB)

    Fusaro, Adriana F. [University of Sydney, NSW 2006 (Australia); CSIRO Plant Industry, Canberra, P.O. Box 1600, ACT 2601 (Australia); Correa, Regis L. [CSIRO Plant Industry, Canberra, P.O. Box 1600, ACT 2601 (Australia); Depto. de Virologia, IMPPG, UFRJ, 21941-902 (Brazil); Nakasugi, Kenlee; Jackson, Craig [University of Sydney, NSW 2006 (Australia); Kawchuk, Lawrence [Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB T1J4B1 (Canada); Vaslin, Maite F.S. [Depto. de Virologia, IMPPG, UFRJ, 21941-902 (Brazil); Waterhouse, Peter M., E-mail: peter.waterhouse@sydney.edu.au [University of Sydney, NSW 2006 (Australia); CSIRO Plant Industry, Canberra, P.O. Box 1600, ACT 2601 (Australia)

    2012-05-10

    The P0 protein of poleroviruses and P1 protein of sobemoviruses suppress the plant's RNA silencing machinery. Here we identified a silencing suppressor protein (SSP), P0{sup PE}, in the Enamovirus Pea enation mosaic virus-1 (PEMV-1) and showed that it and the P0s of poleroviruses Potato leaf roll virus and Cereal yellow dwarf virus have strong local and systemic SSP activity, while the P1 of Sobemovirus Southern bean mosaic virus supresses systemic silencing. The nuclear localized P0{sup PE} has no discernable sequence conservation with known SSPs, but proved to be a strong suppressor of local silencing and a moderate suppressor of systemic silencing. Like the P0s from poleroviruses, P0{sup PE} destabilizes AGO1 and this action is mediated by an F-box-like domain. Therefore, despite the lack of any sequence similarity, the poleroviral and enamoviral SSPs have a conserved mode of action upon the RNA silencing machinery.

  6. Antagonism of Bacillus spp. against Xanthomonas campestris pv. campestris

    Directory of Open Access Journals (Sweden)

    Leila Monteiro

    2005-01-01

    Full Text Available The antagonism of eight Bacillus isolates was investigated against nine strains of Xanthomonas campestris pv. campestris (causal agent of crucifers black rot to assess the role of lipopeptides in this process. Antimicrobial and hemolytic (surfactant activity tests were performed in vitro using agar diffusion methods. Antibiosis and hemolysis were positive for four Bacillus isolates against all X. campestris pv. campestris strains. The correlation observed between antimicrobial and hemolytic activities indicated that lipopeptides were involved in the antibiosis mechanism of the studied antagonists. Fermentation studies were carried out with the isolates that showed highest antimicrobial and hemolytic activities, to follow up growth and production of bioactive and surfactant compounds. Production of bioactive and surfactant compounds was observed during the late growth phase of the Bacillus isolates.Investigação sobre o antagonismo de oito isolados de Bacillus: B. subtilis R14, B. megaterium pv. cerealis RAB7, B. megaterium pv. cerealis C211, B. megaterium C116, Bacillus sp. RAB9, B. cereus C240, Bacillus sp. C11 e B. cereus C210, contra nove linhagens de X. campestris pv. campestris (bactéria responsável pela podridão negra das crucíferas foi realizada para se verificar a participação de lipopeptídeos neste mecanismo. Testes de atividades antimicrobiana e hemolítica (surfactante foram realizados, utilizando-se o método de difusão em ágar. Antibiose e hemólise foram positivas para quatro isolados de Bacillus: R14, RAB7, C116 e C210. A correlação observada entre as atividades antimicrobiana e a hemolítica indica que lipopeptídeos estão envolvidos no mecanismo de antibiose dos isolados investigados. As fermentações foram realizadas com os isolados que demonstraram melhores resultados nos testes de atividades antimicrobiana e hemolítica: R14, RAB7 e C116, para acompanhar o crescimento e a produção de compostos bioativos e

  7. Effect of HIV-1 Env on SERINC5 Antagonism.

    Science.gov (United States)

    Beitari, Saina; Ding, Shilei; Pan, Qinghua; Finzi, Andrés; Liang, Chen

    2017-02-15

    SERINC5 is able to restrict HIV-1 infection by drastically impairing the infectivity of viral particles. Studies have shown that the HIV-1 Nef protein counters SERINC5 through downregulating SERINC5 from the cell surface and preventing the virion incorporation of SERINC5. In addition, the Env proteins of some HIV-1 strains can also overcome SERINC5 inhibition. However, it is unclear how HIV-1 Env does so and why HIV-1 has two mechanisms to resist SERINC5 inhibition. The results of this study show that neither Env nor Nef prevents high levels of ectopic SERINC5 from being incorporated into HIV-1 particles, except that Env, but not Nef, is able to resist inhibition by virion-associated SERINC5. Testing of a panel of HIV-1 Env proteins from different subtypes revealed a high frequency of SERINC5-resistant Envs. Interestingly, although the SERINC5-bearing viruses were not inhibited by SERINC5 itself, they became more sensitive to the CCR5 inhibitor maraviroc and some neutralizing antibodies than the SERINC5-free viruses, which suggests a possible influence of SERINC5 on Env function. We conclude that HIV-1 Env is able to overcome SERINC5 without preventing SERINC5 virion incorporation. HIV-1 Nef is known to enhance the infectivity of HIV-1 particles and to contribute to the maintenance of high viral loads in patients. However, the underlying molecular mechanism remained elusive until the recent discovery of the antiviral activity of SERINC5. SERINC5 profoundly inhibits HIV-1 but is antagonized by Nef, which prevents the incorporation of SERINC5 into viral particles. Here, we show that HIV-1 Env, but not Nef, is able to resist high levels of SERINC5 without excluding SERINC5 from incorporation into viral particles. However, the virion-associated SERINC5 renders HIV-1 more sensitive to some broadly neutralizing antibodies. It is possible that, under the pressure of some neutralizing antibodies in vivo, HIV-1 needs Nef to remove SERINC5 from viral particles, even though

  8. Context-dependent antagonism between Akt inhibitors and topoisomerase poisons.

    Science.gov (United States)

    Gálvez-Peralta, Marina; Flatten, Karen S; Loegering, David A; Peterson, Kevin L; Schneider, Paula A; Erlichman, Charles; Kaufmann, Scott H

    2014-05-01

    Signaling through the phosphatidylinositol-3 kinase (PI3K)/Akt pathway, which is aberrantly activated in >50% of carcinomas, inhibits apoptosis and contributes to drug resistance. Accordingly, several Akt inhibitors are currently undergoing preclinical or early clinical testing. To examine the effect of Akt inhibition on the activity of multiple widely used classes of antineoplastic agents, human cancer cell lines were treated with the Akt inhibitor A-443654 [(2S)-1-(1H-indol-3-yl)-3-[5-(3-methyl-2H-indazol-5-yl)pyridin-3-yl]oxypropan-2-amine; ATP-competitive] or MK-2206 (8-[4-(1-aminocyclobutyl)phenyl]-9-phenyl-2H-[1,2,4]triazolo[3,4-f][1,6]naphthyridin-3-one;dihydrochloride; allosteric inhibitor) or with small interfering RNA (siRNA) targeting phosphoinositide-dependent kinase 1 (PDK1) along with cisplatin, melphalan, camptothecin, or etoposide and assayed for colony formation. Surprisingly different results were observed when Akt inhibitors were combined with different drugs. Synergistic effects were observed in multiple cell lines independent of PI3K pathway status when A-443654 or MK-2206 was combined with the DNA cross-linking agents cisplatin or melphalan. In contrast, effects of the Akt inhibitors in combination with camptothecin or etoposide were more complicated. In HCT116 and DLD1 cells, which harbor activating PI3KCA mutations, A-443654 over a broad concentration range enhanced the effects of camptothecin or etoposide. In contrast, in cell lines lacking activating PI3KCA mutations, partial inhibition of Akt signaling synergized with camptothecin or etoposide, but higher A-443654 or MK-2206 concentrations (>80% inhibition of Akt signaling) or PDK1 siRNA antagonized the topoisomerase poisons by diminishing DNA synthesis, a process that contributes to effective DNA damage and killing by these agents. These results indicate that the effects of combining inhibitors of the PI3K/Akt pathway with certain classes of chemotherapeutic agents might be more

  9. Antagonism of morphine-induced central respiratory depression by donepezil in the anesthetized rabbit

    Directory of Open Access Journals (Sweden)

    MIKI TSUJITA

    2007-01-01

    Full Text Available Morphine is often used in cancer pain and postoperative analgesic management but induces respiratory depression. Therefore, there is an ongoing search for drug candidates that can antagonize morphine-induced respiratory depression but have no effect on morphine-induced analgesia. Acetylcholine is an excitatory neurotransmitter in central respiratory control and physostigmine antagonizes morphine-induced respiratory depression. However, physostigmine has not been applied in clinical practice because it has a short action time, among other characteristics. We therefore asked whether donepezil (a long-acting acetylcholinesterase inhibitor used in the treatment of Alzheimer's disease can antagonize morphine-induced respiratory depression. Using the anesthetized rabbit as our model, we measured phrenic nerve discharge as an index of respiratory rate and amplitude. We compared control indices with discharges after the injection of morphine and after the injection of donepezil. Morphine-induced depression of respiratory rate and respiratory amplitude was partly antagonized by donepezil without any effect on blood pressure and end-tidal C0(2. In the other experiment, apneic threshold PaC0(2 was also compared. Morphine increased the phrenic nerve apnea threshold but this was antagonized by donepezil. These findings indicate that systemically administered donepezil partially restores morphine-induced respiratory depression and morphine-deteriorated phrenic nerve apnea threshold in the anesthetized rabbit

  10. Zinc finger protein 521 antagonizes early B-cell factor 1 and modulates the B-lymphoid differentiation of primary hematopoietic progenitors.

    Science.gov (United States)

    Mega, Tiziana; Lupia, Michela; Amodio, Nicola; Horton, Sarah J; Mesuraca, Maria; Pelaggi, Daniela; Agosti, Valter; Grieco, Michele; Chiarella, Emanuela; Spina, Raffaella; Moore, Malcolm A S; Schuringa, Jan Jacob; Bond, Heather M; Morrone, Giovanni

    2011-07-01

    Zinc finger protein 521 (EHZF/ZNF521) is a multi-functional transcription co-factor containing 30 zinc fingers and an amino-terminal motif that binds to the nucleosome remodelling and histone deacetylase (NuRD) complex. ZNF521 is believed to be a relevant player in the regulation of the homeostasis of the hematopoietic stem/progenitor cell compartment, however the underlying molecular mechanisms are still largely unknown. Here, we show that this protein plays an important role in the control of B-cell development by inhibiting the activity of early B-cell factor-1 (EBF1), a master factor in B-lineage specification. In particular, our data demonstrate that: (1) ZNF521 binds to EBF1 via its carboxyl-terminal portion and this interaction is required for EBF1 inhibition; (2) NuRD complex recruitment by ZNF521 is not essential for the inhibition of transactivation of EBF1-dependent promoters; (3) ZNF521 represses EBF1 target genes in a human B-lymphoid molecular context; and (4) RNAi-mediated silencing of ZNF521/Zfp521 in primary human and murine hematopoietic progenitors strongly enhances the generation of B-lymphocytes in vitro. Taken together, our data indicate that ZNF521 can antagonize B-cell development and lend support to the notion that it may contribute to conserve the multipotency of primitive lympho-myeloid progenitors by preventing or delaying their EBF1-driven commitment toward the B-cell lineage.

  11. Anti-viral RNA silencing: do we look like plants ?

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    Lecellier Charles-Henri

    2006-01-01

    Full Text Available Abstract The anti-viral function of RNA silencing was first discovered in plants as a natural manifestation of the artificial 'co-suppression', which refers to the extinction of endogenous gene induced by homologous transgene. Because silencing components are conserved among most, if not all, eukaryotes, the question rapidly arose as to determine whether this process fulfils anti-viral functions in animals, such as insects and mammals. It appears that, whereas the anti-viral process seems to be similarly conserved from plants to insects, even in worms, RNA silencing does influence the replication of mammalian viruses but in a particular mode: micro(miRNAs, endogenous small RNAs naturally implicated in translational control, rather than virus-derived small interfering (siRNAs like in other organisms, are involved. In fact, these recent studies even suggest that RNA silencing may be beneficial for viral replication. Accordingly, several large DNA mammalian viruses have been shown to encode their own miRNAs. Here, we summarize the seminal studies that have implicated RNA silencing in viral infection and compare the different eukaryotic responses.

  12. Precedents and consequences of prosocial behaviors of voice and silence

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    Alicia Omar

    2015-09-01

    Full Text Available Prosocial behavior is that which that encourages solidarity and harmony in interpersonal relationships, and produce personal or collective benefits. Although early research on job prosociality was focused on the study of conventional behaviors such as help, courtesy and sportsmanship, the identification and operationalization of new dimensions is rapidly expanding this nomological network. Such is the case of prosocial voice and prosocial silence, recently introduced in the scientific literature. The aim of this study is to explore possible relationships between employee’s voice and employee’s silence, and their personality structure; and examine the role of interpersonal justice perceptions on such relationships. We worked with a sample of 316 employees- aged 37 years and holding a 4.2-year signority working at public and private companies in southern and central Rosario (Argentina. The subjects completed Colquitt’ Justice Organizational Scale, Eysenck Personality Questionnaire, and Van Dyne’s Prosocial Voice and Prosocial Silence Scales. Extraversion and neuroticism emerged as the strongest predictors of prosocial voice and prosocial silence, respectively. Interpersonal justice perceptions emerged as moderators of the ‘natural’ tendency of extraverted workers to engage in prosocial voice, and emotionally controlled workers to engage in prosocial silence. Such findings would indicate that the promotion of high levels of interpersonal justice on job contexts could help workers to engage in more prosocial behavior with positive effects for the organization. 

  13. RELATIONSHIP BETWEEN AFFECTIVE COMMITMENT ANDORGANIZATIONAL SILENCE: A CONCEPTUAL DISCUSSION

    Directory of Open Access Journals (Sweden)

    Fitnat Nazlı Sayğan

    2011-07-01

    Full Text Available In this study, the affective commitment that is oneof the components oforganizational commitment put forth by Allen and Meyer (Allen, Meyer 1996will be differentiated from the other commitment components. The importance ofcreating an emotional commitment to organizations will be examined and theorganizational factors needed to form organizational commitment will beinvestigated. Also, organizational silence is a situation that the company avoided.In the study, the reasons and the drawbacks of silence are focused on and thefactors that cause employees to remain silent are discussed.The aim of this study is intended to manifest the relationship of ‘organizationalsilence' with affective commitment’ which is one ofthe components of‘organizational commitment’ on the basis of literature. In this study, a negativecorrelation between affective commitment and organizational silence is suggested

  14. RNA silencing can explain chlorotic infection patterns on plant leaves

    Directory of Open Access Journals (Sweden)

    Hogeweg Paulien

    2008-11-01

    Full Text Available Abstract Background RNA silencing has been implicated in virus symptom development in plants. One common infection symptom in plants is the formation of chlorotic tissue in leaves. Chlorotic and healthy tissue co-occur on a single leaf and form patterns. It has been shown that virus levels in chlorotic tissue are high, while they are low in healthy tissue. Additionally, the presence of siRNAs is confined to the chlorotic spots and the boundaries between healthy and infected tissue. These results strongly indicate that the interaction between virus growth and RNA silencing plays a role in the formation of infection patterns on leaves. However, how RNA silencing leads to the intricate patterns is not known. Results Here we elucidate the mechanisms leading to infection patterns and the conditions which lead to the various patterns observed. We present a modeling approach in which we combine intra- and inter-cellular dynamics of RNA silencing and viral growth. We observe that, due to the spread of viruses and the RNA silencing response, parts of the tissue become infected while other parts remain healthy. As is observed in experiments high virus levels coincide with high levels of siRNAs, and siRNAs are also present in the boundaries between infected and healthy tissue. We study how single- and double-stranded cleavage by Dicer and amplification by RNA-dependent RNA polymerase can affect the patterns formed. Conclusion This work shows that RNA silencing and virus growth within a cell, and the local spread of virions and siRNAs between cells can explain the heterogeneous spread of virus in leaf tissue, and therewith the observed infection patterns in plants.

  15. Friction coefficient measurements of silencers on specialized duct tract

    Directory of Open Access Journals (Sweden)

    Sehnalek Stanislav

    2016-01-01

    Full Text Available This article describes test methods on air duct track in Laboratory of Environmental Engineering. It focuses on measurement of silencer parameter like is pressure loss coeffcient. Firstly, the paper describe the measurement apparatus with description of calculation method by standard ISO 7235 and energy equation. Then the paper presents three ways how to accomplish measurement because such way is not covered by procedure in standard. Then follows the evaluation of results of measurements on three types of silencer designed for HVAC applications. The article is concluded with discussion over measured data with outline for further research.

  16. Re-discovery of silence in pastoral care.

    Science.gov (United States)

    Moriichi, Shuji

    2009-01-01

    Pastoral care within the greater American cultural milieu strongly appraises the use of spoken words and tends to undervalue silence as a powerful and creative element for mutual connection with others and with God. In this essay the author proposes a "counter-cultural" adjustment in the perception of silence and its implications to the practice of, and theological understanding of, pastoral care. The author bases his theses on his own cross-cultural learning experiences, including his training in Clinical Pastoral Education (CPE), in the re-vitalization of ancient Christian wisdom, and in his current ministry to nursing home residents.

  17. The epigenetic modifier PRDM5 functions as a tumor suppressor through modulating WNT/β-catenin signaling and is frequently silenced in multiple tumors.

    Directory of Open Access Journals (Sweden)

    Xing-sheng Shu

    Full Text Available BACKGROUND: PRDM (PRDI-BF1 and RIZ domain containing proteins are zinc finger proteins involved in multiple cellular regulations by acting as epigenetic modifiers. We studied a recently identified PRDM member PRDM5 for its epigenetic abnormality and tumor suppressive functions in multiple tumorigeneses. METHODOLOGY/PRINCIPAL FINDINGS: Semi-quantitative RT-PCR showed that PRDM5 was broadly expressed in human normal tissues, but frequently silenced or downregulated in multiple carcinoma cell lines due to promoter CpG methylation, including 80% (4/5 nasopharyngeal, 44% (8/18 esophageal, 76% (13/17 gastric, 50% (2/4 cervical, and 25% (3/12 hepatocellular carcinoma cell lines, but not in any immortalized normal epithelial cell lines. PRDM5 expression could be restored by 5-aza-2'-deoxycytidine demethylation treatment in silenced cell lines. PRDM5 methylation was frequently detected by methylation-specific PCR (MSP in multiple primary tumors, including 93% (43/46 nasopharyngeal, 58% (25/43 esophageal, 88% (37/42 gastric and 63% (29/46 hepatocellular tumors. PRDM5 was further found a stress-responsive gene, but its response was impaired when the promoter was methylated. Ectopic PRDM5 expression significantly inhibited tumor cell clonogenicity, accompanied by the inhibition of TCF/β-catenin-dependent transcription and downregulation of CDK4, TWIST1 and MDM2 oncogenes, while knocking down of PRDM5 expression lead to increased cell proliferation. ChIP assay showed that PRDM5 bound to its target gene promoters and suppressed their transcription. An inverse correlation between the expression of PRDM5 and activated β-catenin was also observed in cell lines. CONCLUSIONS/SIGNIFICANCE: PRDM5 functions as a tumor suppressor at least partially through antagonizing aberrant WNT/β-catenin signaling and oncogene expression. Frequent epigenetic silencing of PRDM5 is involved in multiple tumorigeneses, which could serve as a tumor biomarker.

  18. An Abundant Class of Non-coding DNA Can Prevent Stochastic Gene Silencing in the C. elegans Germline

    DEFF Research Database (Denmark)

    Frøkjær-Jensen, Christian; Jain, Nimit; Hansen, Loren

    2016-01-01

    Cells benefit from silencing foreign genetic elements but must simultaneously avoid inactivating endogenous genes. Although chromatin modifications and RNAs contribute to maintenance of silenced states, the establishment of silenced regions will inevitably reflect underlying DNA sequence and/or s...

  19. Mutualism and Antagonism: Ecological Interactions Among Bark Beetles, Mite and Fungi

    Science.gov (United States)

    K.D. Klepzig; J.C. Moser; M.J. Lombardero; M.P. Ayres; R.W. Hofstetter; C.J. Walkinshaw

    2001-01-01

    Insect-fungal complexes provide challenging and fascinating systems for the study of biotic interactions between plants. plant pathogens, insect vectors and other associated organisms. The types of interactions among these organisms (mutualism. antagonism. parasitism. phoresy. etc.) are as variable as the range of organisms involved (plants, fungi, insects. mites. etc...

  20. Design and development of benzoxazole derivatives with toll-like receptor 9 antagonism.

    Science.gov (United States)

    Roy, Swarnali; Mukherjee, Ayan; Paul, Barnali; Rahaman, Oindrila; Roy, Shounak; Maithri, Gundaram; Ramya, Bandaru; Pal, Sourav; Ganguly, Dipyaman; Talukdar, Arindam

    2017-07-07

    Toll-like receptor 9 (TLR9) is a major therapeutic target for numerous inflammatory disorders. Development of small molecule inhibitors for TLR9 remains largely empirical due to lack of structural understanding of potential TLR9 antagonism by small molecules and due to the unusual topology of the ligand binding surface of the receptor. To develop a structural model for rational design of small molecule TLR9 antagonists, an enhanced homology model of human TLR9 (hTLR9) was constructed. Binding mode analysis of a series of molecules having characteristic molecular geometry, flexibility and basicity was conducted based on crystal structure of the inhibitory DNA (iDNA) bound to horse and bovine TLR9. Interaction with specific amino acid residues in four leucine rich repeat (LRR) regions of TLR9 was identified to be critical for antagonism by small molecules. The biological validation of TLR9 antagonism and its correlation with probe-receptor interactions led to a reliable model that could be used for development of novel small molecules with potent TLR9 antagonism (IC 50 30-100 nM) with excellent selectivity against TLR7. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  1. Small RNA binding is a common strategy to suppress RNA silencing by several viral suppressors

    Science.gov (United States)

    Lakatos, Lóránt; Csorba, Tibor; Pantaleo, Vitantonio; Chapman, Elisabeth J; Carrington, James C; Liu, Yu-Ping; Dolja, Valerian V; Calvino, Lourdes Fernández; López-Moya, Juan José; Burgyán, József

    2006-01-01

    RNA silencing is an evolutionarily conserved system that functions as an antiviral mechanism in higher plants and insects. To counteract RNA silencing, viruses express silencing suppressors that interfere with both siRNA- and microRNA-guided silencing pathways. We used comparative in vitro and in vivo approaches to analyse the molecular mechanism of suppression by three well-studied silencing suppressors. We found that silencing suppressors p19, p21 and HC-Pro each inhibit the intermediate step of RNA silencing via binding to siRNAs, although the molecular features required for duplex siRNA binding differ among the three proteins. None of the suppressors affected the activity of preassembled RISC complexes. In contrast, each suppressor uniformly inhibited the siRNA-initiated RISC assembly pathway by preventing RNA silencing initiator complex formation. PMID:16724105

  2. Suppressors of RNA silencing encoded by tomato leaf curl ...

    Indian Academy of Sciences (India)

    2013-01-06

    Jan 6, 2013 ... step in the RNA-silencing pathway that occurs after siRNA production (Zrachya et al. 2007). Geminiviruses (family Geminiviridae) are a diverse group of plant viruses with circular single-stranded DNA genomes that are composed of one or two components of 2700–. 3000 bp length which are encapsidated ...

  3. Organizational Justice As a Predictor of Organizational Silence

    Science.gov (United States)

    Tan, Çetin

    2014-01-01

    In this study, relation between teachers' perception for organizational justice and their organizational silence was examined. Sample of this study consists of 300 teachers who work at elementary schools in Siirt. Relational Scanning model was utilized in performance of this study. In this study, Organizational Justice Scale and Organizational…

  4. For the Sake of Silence | Kearney | Current Writing: Text and ...

    African Journals Online (AJOL)

    The Order of Cistercians of the Strict Observance – better known as “Trappists” after their famous monastery, Notre Dame de la Trappe – is the strictest and most ascetic Order in the Catholic Church. In addition to vows of poverty, chastity and obedience taken by all religious, Trappists bind themselves to silence and stability ...

  5. Survivors' Voices Breaking the Silence: Owning the Past.

    Science.gov (United States)

    Benton, Carol L.

    For the adult survivor of incest, the evolution from victim to survivor occurs in complex and creative ways. Often journal writing can be a means of exposing and exploring past abuse. The process of journal writing is special in that it allows the adult survivor to break the silence and shame imposed by the perpetrator while remaining essentially…

  6. Bureaucratic Constructions of Sexual Diversity: "Sensitive", "Controversial" and Silencing

    Science.gov (United States)

    Ullman, Jacqueline; Ferfolja, Tania

    2015-01-01

    National research illustrates the high degree of discrimination that prevails against lesbian, gay, bisexual, transgender and queer (LGBTQ) students resulting in diminished educational outcomes, both academic and social. This phenomenon is influenced by the prevalence of whole-school silences around LGBTQ topics in many Australian schools. This…

  7. Identification of a maize chlorotic dwarf virus silencing suppressor protein.

    Science.gov (United States)

    Stewart, Lucy R; Jarugula, Sridhar; Zhao, Yujing; Qu, Feng; Marty, DeeMarie

    2017-04-01

    Maize chlorotic dwarf virus (MCDV), a member of the genus Waikavirus, family Secoviridae, has a 11784 nt (+)ssRNA genome that encodes a 389kDa proteolytically processed polyprotein. We show that the N-terminal 78kDa polyprotein (R78) of MCDV acts as a suppressor of RNA silencing in a well-established assay system. We further demonstrate that R78 is cleaved by the viral 3C-like protease into 51 and 27kDa proteins (p51 and p27), and that p51 is responsible for silencing suppressor activity. Silencing suppressor activity of R78 is conserved in three divergent MCDV strains (MCDV-Severe, MCDV-M1, and MCDV-Tennessee), as well as the waikavirus Bellflower vein chlorosis virus, but was not detected for orthologous protein of Rice tungro spherical virus (RTSV-A) or the similarly-positioned protein from the sequivirus Parsnip yellow fleck virus (PYFV). This is the first identification of a virus suppressor of RNA silencing encoded by a waikavirus. Copyright © 2017. Published by Elsevier Inc.

  8. The effects of thinking in silence on creativity and innovation

    NARCIS (Netherlands)

    de Vet, A.J.

    2007-01-01

    This dissertation consists of three empirical studies on the effects of thinking in silence on creativity and innovation. In these studies I use a social psychology and cognitive psychology lens to study creativity and innovation at the individual and at the team level of analysis, using randomized

  9. RNAi-based silencing of genes encoding the vacuolar- ATPase ...

    African Journals Online (AJOL)

    RNAi-based silencing of genes encoding the vacuolar- ATPase subunits a and c in pink bollworm (Pectinophora gossypiella). Ahmed M. A. Mohammed. Abstract. RNA interference is a post- transcriptional gene regulation mechanism that is predominantly found in eukaryotic organisms. RNAi demonstrated a successful ...

  10. 47 CFR 80.304 - Watch requirement during silence periods.

    Science.gov (United States)

    2010-10-01

    ....304 Section 80.304 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES STATIONS IN THE MARITIME SERVICES Safety Watch Requirements and Procedures Ship Station Safety Watches § 80.304 Watch requirement during silence periods. Each ship station operating on...

  11. Silence is Golden: The Lack of Direction on Compensation for ...

    African Journals Online (AJOL)

    Silence is Golden: The Lack of Direction on Compensation for Expropriation in the 2011 Green Paper on Land Reform. ... Frustrated at the slow pace of land reform, the ruling party is starting to indicate that the state will in future rely on its expropriation powers to acquire such land. Section 25 of the Constitution makes it ...

  12. Maternal Silences: Motherhood and Voluntary Childlessness in Contemporary Christianity

    Directory of Open Access Journals (Sweden)

    Dawn Llewellyn

    2016-06-01

    Full Text Available In Christianity, there is an ideology of motherhood that pervades scripture, ritual, and doctrine, yet there is an academic silence that means relatively little space has been given to motherhood and mothering, and even less to voluntary childlessness, from a faith perspective. By drawing on qualitative in-depth interviews with Christian women living in Britain, narrating their experiences of motherhood and voluntary childlessness, I suggest there are also lived maternal silences encountered by women in contemporary Christianity. There is a maternal expectation produced through church teaching, liturgy and culture that constructs women as ‘maternal bodies’ (Gatrell 2008; this silences and marginalises women from articulating their complex relationship with religion, motherhood, and childlessness in ways that challenge their spiritual development. However, this article also introduces the everyday and intentional tactics women employ to disrupt the maternal expectation, and hereby interrupt the maternal silence.

  13. Shame and Silence | Janz | South African Journal of Philosophy

    African Journals Online (AJOL)

    Samantha Vice's proposal on how to live in 'this strange place' of contemporary South Africa, includes an appeal to the concepts of shame and silence. In this paper, I use Emmanuel Levinas and Giorgio Agamben to move the discussion of shame from a moral to an existential question. The issue is not about how one ...

  14. Identification of a maize chlorotic dwarf virus silencing suppressor protein

    Science.gov (United States)

    Maize chlorotic dwarf virus (MCDV), a member of the genus Waikavirus, family Secoviridae, has a 11784 nt (+)ssRNA genome that encodes a 389 kDa proteolytically processed polyprotein. We show that an N-terminal 78kDa polyprotein (R78) has silencing suppressor activity, that it is cleaved by the viral...

  15. Relationship between Organizational Mobbing and Silence Behavior among Teachers

    Science.gov (United States)

    Hüsrevsahi, Selda Polat

    2015-01-01

    This study mainly aims to investigate the correlation between teachers' exposure to mobbing in their workplaces and their display of the act of silence. This study is based on a survey design where data from 312 teachers were collected and analyzed using correlation and regression analyses. Specifically, "The Structure and Dimensions of…

  16. Inhibition of tobacco axillary bud differentiation by silencing CUP ...

    African Journals Online (AJOL)

    Yomi

    2012-02-23

    Feb 23, 2012 ... exhibited some important phenotypes, such as leaf fusion, leaf curl and incomplete leaf. CUC3 in N. tabacum was silenced successfully by RNA interference (RNAi), which .... 0.1 mg NAA L-1 and 1.0 mg BAP L-1 was used as co-culture medium. Co-culture medium with hygromycin B 50 mg hygromycin.

  17. Studies of the silencing of Baculovirus DNA binding protein

    NARCIS (Netherlands)

    Quadt, I.; Lent, van J.W.M.; Knebel-Morsdorf, D.

    2007-01-01

    Baculovirus DNA binding protein (DBP) binds preferentially single-stranded DNA in vitro and colocalizes with viral DNA replication sites. Here, its putative role as viral replication factor has been addressed by RNA interference. Silencing of DBP in Autographa californica multiple

  18. Tacit Authorization : A Legal Solution for Administrative Silence

    NARCIS (Netherlands)

    Hoogstra, Nicole; de Graaf, K.J.

    2016-01-01

    This article discusses one of the current legal instruments to stimulate timely decision-making by administrative authorities, namely the ‘Lex silencio positivo’ or the ‘Silence is Consent’ rule. Tacit authorization prescribes that the license sought by the applicant will be granted automatically if

  19. Suppressors of RNA silencing encoded by tomato leaf curl ...

    Indian Academy of Sciences (India)

    In the present study suppressor function of ORF C1 of three betasatellites Tomato leaf curl Bangalore betasatellite ToLCBB-[IN:Hess:08], Cotton leaf curl Multan betasatellite CLCuMB–[IN:Sri:02] and Luffa leaf distortion betasatellite LuLDB-[IN:Lu:04] were examined. Agroinfiltration of GFP-silenced Nicotiana tabaccum cv.

  20. Mobile gene silencing in Arabidopsis is regulated by hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Dacheng Liang

    2014-12-01

    Full Text Available In plants and nematodes, RNAi can spread from cells from which it is initiated to other cells in the organism. The underlying mechanism controlling the mobility of RNAi signals is not known, especially in the case of plants. A genetic screen designed to recover plants impaired in the movement but not the production or effectiveness of the RNAi signal identified RCI3, which encodes a hydrogen peroxide (H2O2-producing type III peroxidase, as a key regulator of silencing mobility in Arabidopsis thaliana. Silencing initiated in the roots of rci3 plants failed to spread into leaf tissue or floral tissue. Application of exogenous H2O2 reinstated the spread in rci3 plants and accelerated it in wild-type plants. The addition of catalase or MnO2, which breaks down H2O2, slowed the spread of silencing in wild-type plants. We propose that endogenous H2O2, under the control of peroxidases, regulates the spread of gene silencing by altering plasmodesmata permeability through remodelling of local cell wall structure, and may play a role in regulating systemic viral defence.

  1. Is our knowledge of voice and silence in organizations growing?

    DEFF Research Database (Denmark)

    Knoll, Michael; Wegge, Jürgen; Unterrainer, Christine

    2016-01-01

    This article has three objectives. Firstly, we seek to demonstrate the relevance of voice and silence – that is, whether employees contribute or withhold information, ideas, views and/or concerns at work – for the sustainable development of individuals, organizations and societies. Our second obj...

  2. Silencing of HMGA2 promotes apoptosis and inhibits migration and ...

    Indian Academy of Sciences (India)

    2016-04-05

    Apr 5, 2016 ... Silencing of HMGA2 promotes apoptosis and inhibits migration and invasion of prostate cancer cells. ZHAN SHI, DING WU, RUN TANG, XIANG LI, RENFU CHEN, SONG XUE, CHENGJING ZHANG and XIAOQING SUN*. Department of Urology, The Affiliated Hospital of Xuzhou Medical College,. Xuzhou ...

  3. RNAi-based silencing of genes encoding the vacuolar- ATPase ...

    African Journals Online (AJOL)

    2016-11-09

    Nov 9, 2016 ... Spodoptera exigua larval development by silencing chitin synthase gene with RNA interference. Bull. Entomol. Res. 98:613-619. Dow JAT (1999). The Multifunctional Drosophila melanogaster V-. ATPase is encoded by a multigene family. J. Bioenerg. Biomembr. 31:75-83. Fire A, Xu SQ, Montgomery MK, ...

  4. Breaking the Silence Surrounding Mental Health on Campus

    Science.gov (United States)

    Roper, Larry D.

    2013-01-01

    Mentally ill students are able to participate in higher education at unprecedented rates. While colleges and universities have been responsive to the therapeutic needs, we have failed to successfully create supportive campus climates. Campus leaders are challenged to demonstrate ethical leadership that breaks the silence and confronts the stigma…

  5. MGMT gene silencing and benefit from temozolomide in glioblastoma

    NARCIS (Netherlands)

    Hegi, ME; Diserens, A; Gorlia, T; Hamou, M; de Tribolet, N; Weller, M; Kros, JM; Hainfellner, JA; Mason, W; Mariani, L; Bromberg, JEC; Hau, P; Mirimanoff, RO; Cairncross, JG; Janzer, RC; Stupp, R

    2005-01-01

    BACKGROUND: Epigenetic silencing of the MGMT (O(sup 6)-methylguanine-DNA methyltransferase) DNA-repair gene by promoter methylation compromises DNA repair and has been associated with longer survival in patients with glioblastoma who receive alkylating agents. METHODS: We tested the relationship

  6. Suppressors of RNA silencing encoded by tomato leaf curl ...

    Indian Academy of Sciences (India)

    2013-01-06

    Jan 6, 2013 ... satellite DNA β which are predicted to function as silencing suppressors. In the present study suppressor function ... of plant viruses with circular single-stranded DNA genomes that are composed of one or two components of ..... 1 2 3 4 5 6 7 8 9 10 11 12 13 14 M. Figure 4. Southern blot analysis of DNA ...

  7. The code of silence: Revisiting South African police integrity | Ivkovic ...

    African Journals Online (AJOL)

    ... results provide further evidence of the presence of the code of silence covering various forms of police misconduct. At least one quarter of the respondents would protect a fellow officer who verbally abused citizens, covered up police driving under the influence (DUI) accident, accepted gratuities, or failed to react to graffiti.

  8. Strain Specific Factors Control Effector Gene Silencing in Phytophthora sojae.

    Directory of Open Access Journals (Sweden)

    Sirjana Devi Shrestha

    Full Text Available The Phytophthora sojae avirulence gene Avr3a encodes an effector that is capable of triggering immunity on soybean plants carrying the resistance gene Rps3a. P. sojae strains that express Avr3a are avirulent to Rps3a plants, while strains that do not are virulent. To study the inheritance of Avr3a expression and virulence towards Rps3a, genetic crosses and self-fertilizations were performed. A cross between P. sojae strains ACR10 X P7076 causes transgenerational gene silencing of Avr3a allele, and this effect is meiotically stable up to the F5 generation. However, test-crosses of F1 progeny (ACR10 X P7076 with strain P6497 result in the release of silencing of Avr3a. Expression of Avr3a in the progeny is variable and correlates with the phenotypic penetrance of the avirulence trait. The F1 progeny from a direct cross of P6497 X ACR10 segregate for inheritance for Avr3a expression, a result that could not be explained by parental imprinting or heterozygosity. Analysis of small RNA arising from the Avr3a gene sequence in the parental strains and hybrid progeny suggests that the presence of small RNA is necessary but not sufficient for gene silencing. Overall, we conclude that inheritance of the Avr3a gene silenced phenotype relies on factors that are variable among P. sojae strains.

  9. Marie Nimier, au cœur du silence

    Directory of Open Access Journals (Sweden)

    Joëlle Papillon

    2012-01-01

    Full Text Available Dans La Reine du silence, Marie Nimier se confronte à la figure de son père, l’écrivain Roger Nimier, mort lorsqu’elle avait cinq ans. Elle y montre le poids qui pèse sur l’enfant d’écrivain, mais aussi celui de l’héritage du secret familial et de l’injonction au silence. La difficulté de l’élaboration de son récit de filiation se révèle dans les constants recommencements et reformulations, qui constituent la marque de la tension angoissante entre l’obligation de dire et celle de taire. In La Reine du silence, Marie Nimier confronts her father’s memory – the writer Roger Nimier, who died when she was five years old. The novel describes the burden of being a writer’s child, along with that of inheriting family secrets and submitting to a code of silence. The difficulty of recounting her relationship with her late father is evidenced by the narrator’s numerous “false starts” and her constant rewritings. The hesitant nature of the narration captures an anguish born of two irreconcilable obligations : the need to put things into words and the pressure to remain silent.

  10. Assessment of RNAi-induced silencing in banana (Musa spp.).

    Science.gov (United States)

    Dang, Tuong Vi T; Windelinckx, Saskia; Henry, Isabelle M; De Coninck, Barbara; Cammue, Bruno P A; Swennen, Rony; Remy, Serge

    2014-09-18

    In plants, RNA- based gene silencing mediated by small RNAs functions at the transcriptional or post-transcriptional level to negatively regulate target genes, repetitive sequences, viral RNAs and/or transposon elements. Post-transcriptional gene silencing (PTGS) or the RNA interference (RNAi) approach has been achieved in a wide range of plant species for inhibiting the expression of target genes by generating double-stranded RNA (dsRNA). However, to our knowledge, successful RNAi-application to knock-down endogenous genes has not been reported in the important staple food crop banana. Using embryogenic cell suspension (ECS) transformed with ß-glucuronidase (GUS) as a model system, we assessed silencing of gusAINT using three intron-spliced hairpin RNA (ihpRNA) constructs containing gusAINT sequences of 299-nt, 26-nt and 19-nt, respectively. Their silencing potential was analysed in 2 different experimental set-ups. In the first, Agrobacterium-mediated co-transformation of banana ECS with a gusAINT containing vector and an ihpRNA construct resulted in a significantly reduced GUS enzyme activity 6-8 days after co-cultivation with either the 299-nt and 19-nt ihpRNA vectors. In the second approach, these ihpRNA constructs were transferred to stable GUS-expressing ECS and their silencing potential was evaluated in the regenerated in vitro plants. In comparison to control plants, transgenic plants transformed with the 299-nt gusAINT targeting sequence showed a 4.5 fold down-regulated gusA mRNA expression level, while GUS enzyme activity was reduced by 9 fold. Histochemical staining of plant tissues confirmed these findings. Northern blotting used to detect the expression of siRNA in the 299-nt ihpRNA vector transgenic in vitro plants revealed a negative relationship between siRNA expression and GUS enzyme activity. In contrast, no reduction in GUS activity or GUS mRNA expression occurred in the regenerated lines transformed with either of the two gusAINT oligo target

  11. "I Don't Want to Hear That!": Legitimating Whiteness through Silence in Schools

    Science.gov (United States)

    Castagno, Angelina E.

    2008-01-01

    In this article, I examine the ways in which silences around race contribute to the maintenance and legitimation of Whiteness. Drawing on ethnographic data from two demographically different schools, I highlight patterns of racially coded language, teacher silence, silencing students' race talk, and the conflating of culture with race, equality…

  12. Eloquent silences: A musical and lexical analysis of conversation between oncologists and their patients.

    Science.gov (United States)

    Bartels, Josef; Rodenbach, Rachel; Ciesinski, Katherine; Gramling, Robert; Fiscella, Kevin; Epstein, Ronald

    2016-10-01

    Silences in doctor-patient communication can be "connectional" and communicative, in contrast to silences that indicate awkwardness or distraction. Musical and lexical analyses can identify and characterize connectional silences in consultations between oncologists and patients. Two medical students and a professor of voice screened all 1211 silences over 2s in length from 124 oncology office visits. We developed a "strength of connection" taxonomy and examined ten connectional silences for lexical and musical features including pitch, volume, and speaker turn-taking rhythm. We identified connectional silences with good reliability. Typical dialog rhythms surrounding connectional silences are characterized by relatively equal turn lengths and frequent short vocalizations. We found no pattern of volume and pitch variability around these silences. Connectional silences occurred in a wide variety of lexical contexts. Particular patterns of dialog rhythm mark connectional silences. Exploring structures of connectional silence extends our understanding of the audio-linguistic conditions that mark patient-clinician connection. Communicating with an awareness of pitch, rhythm, and silence - in addition to lexical content - can facilitate shared understanding and emotional connection. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. RNA-mediated gene silencing of superoxide dismutase (bcsod1) in Botrytis cinerea

    NARCIS (Netherlands)

    Patel, R.M.; Kan, van J.A.L.; Bailey, A.M.; Foster, G.D.

    2008-01-01

    Gene silencing is a powerful tool utilized for identification of gene function and analysis in plants, animals, and fungi. Here, we report the silencing of superoxide dismutase (bcsod1) in Botrytis cinerea through sense and antisense-mediated silencing mechanisms. Because superoxide dismutase (SOD)

  14. Simultaneous Silencing of Xylanase Genes in Botrytis cinerea

    Directory of Open Access Journals (Sweden)

    Néstor García

    2017-12-01

    Full Text Available The endo-β-1,4-xylanase BcXyn11A is one of several plant cell-wall degrading enzymes that the phytopathogenic fungus Botrytis cinerea secretes during interaction with its hosts. In addition to its enzymatic activity, this protein also acts as an elicitor of the defense response in plants and has been identified as a virulence factor. In the present work, other four endoxylanase coding genes (Bcxyn11B, Bcxyn11C, Bcxyn10A, and Bcxyn10B were identified in the B. cinerea genome and the expression of all five genes was analyzed by Q-RT- PCR in vitro and in planta. A cross-regulation between xylanase genes was identified analyzing their expression pattern in the ΔBcxyn11A mutant strain and a putative BcXyn11A-dependt induction of Bcxyn10B gene was found. In addition, multiple knockdown strains were obtained for the five endoxylanase genes by transformation of B. cinerea with a chimeric DNA construct composed of 50-nt sequences from the target genes. The silencing of each xylanase gene was analyzed in axenic cultures and during infection and the results showed that the efficiency of the multiple silencing depends on the growth conditions and on the cross-regulation between them. Although the simultaneous silencing of the five genes was observed by Q-RT-PCR when the silenced strains were grown on medium supplemented with tomato extract, the endoxylanase activity measured in the supernatants was reduced only by 40%. Unexpectedly, the silenced strains overexpressed the Bcxyn11A and Bcxyn11C genes during the infection of tomato leaves, making difficult the analysis of the role of the endo-β-1,4-xylanases in the virulence of the fungus.

  15. Toward a science of silence: The consequences of leaving a memory unsaid

    DEFF Research Database (Denmark)

    Stone, Charles; Coman, Alin; Brown, Adam

    2012-01-01

    Silence about the past permeates acts of remembering, with marked mnemonic consequences. Mnemonic silence—the absence of expressing a memory—is public in nature and is embedded within communicative acts, such as conversations. As such, silence has the potential to affect both speakers—the source...... the silence is intentional or unintentional, and whether the silenced memory is related or unrelated to the memories emerging in a conversation. These factors appear to be critical when considering the mnemonic consequences. Moreover, the influence of silence on memory varies between speaker and listener...

  16. Does gestrinone antagonize the effects of estrogen on endometrial implants upon the peritoneum of rats?

    Directory of Open Access Journals (Sweden)

    Vera Lúcia Rodrigues Lobo

    2008-01-01

    Full Text Available OBJECTIVE: To evaluate the effects of estrogen treatment in combination with gestrinone on an experimental rat model of endometriosis. METHODS: Uterine transplants were attached to the peritoneum of female Wistar rats via a surgical autotransplantation technique. The implanted area was measured during the proestrus phase and after hormonal treatment. We performed morphometric analysis and examined the macroscopic and morphometric alterations of endometrial implants after hormonal treatment in ovariectomized rats. RESULTS: The high dose of estrogen caused macroscopic increases in the endometrial implant group compared with other groups, which were similar to increases in the proestrus phase. The low dose showed morphometric development of implants, such as an increase in number of endometrial glands, leukocyte infiltration and mitosis. Gestrinone antagonized both doses of estrogen. CONCLUSION: Our findings suggest that gestrinone antagonizes estrogen's effects on rat peritoneal endometrial implants.

  17. Three distinct suppressors of RNA silencing encoded by a 20-kb viral RNA genome

    Science.gov (United States)

    Lu, Rui; Folimonov, Alexey; Shintaku, Michael; Li, Wan-Xiang; Falk, Bryce W.; Dawson, William O.; Ding, Shou-Wei

    2004-11-01

    Viral infection in both plant and invertebrate hosts requires a virus-encoded function to block the RNA silencing antiviral defense. Here, we report the identification and characterization of three distinct suppressors of RNA silencing encoded by the 20-kb plus-strand RNA genome of citrus tristeza virus (CTV). When introduced by genetic crosses into plants carrying a silencing transgene, both p20 and p23, but not coat protein (CP), restored expression of the transgene. Although none of the CTV proteins prevented DNA methylation of the transgene, export of the silencing signal (capable of mediating intercellular silencing spread) was detected only from the F1 plants expressing p23 and not from the CP- or p20-expressing F1 plants, demonstrating suppression of intercellular silencing by CP and p20 but not by p23. Thus, intracellular and intercellular silencing are each targeted by a CTV protein, whereas the third, p20, inhibits silencing at both levels. Notably, CP suppresses intercellular silencing without interfering with intracellular silencing. The novel property of CP suggests a mechanism distinct to p20 and all of the other viral suppressors known to interfere with intercellular silencing and that this class of viral suppressors may not be consistently identified by Agrobacterium coinfiltration because it also induces RNA silencing against the infiltrated suppressor transgene. Our analyses reveal a sophisticated viral counter-defense strategy that targets the silencing antiviral pathway at multiple steps and may be essential for protecting CTV with such a large RNA genome from antiviral silencing in the perennial tree host. RNA interference | citrus tristeza virus | virus synergy | antiviral immunity

  18. [An analysis of "silence" in public opinion about public works].

    Science.gov (United States)

    Fujii, Satoshi

    2007-06-01

    An Internet survey targeting at from 200 to 500 samples in every prefecture in Japan (n=15,316) was conducted in order to analyze the expression of attitudes or silence regarding public works. The data indicated those who had different attitudes from the perceived public attitude were likely to express their attitudes, those whose attitude was neutral were not likely to express it, and those with positive attitudes were likely to express more than those with negative attitudes. The tendency that those with positive attitudes were more likely to express them than those with negative attitudes decreased as the residential population increased. Those with positive attitudes in Tokyo kept "silence" regarding their attitudes, similar to those with neutral attitudes. Analysis regarding the attitudes in different prefectures indicated that attitudes toward public works were positively related to the yearly public stake in the prefecture.

  19. cDNA libraries for virus-induced gene silencing.

    Science.gov (United States)

    Todd, Andrea T; Liu, Enwu; Page, Jonathan E

    2010-01-01

    Virus-induced gene silencing (VIGS) exploits endogenous plant antiviral defense mechanisms to posttranscriptionally silence the expression of targeted plant genes. VIGS is quick and relatively easy to perform and therefore serves as a powerful tool for high-throughput functional genomics in plants. Combined with the use of subtractive cDNA libraries for generating a collection of VIGS-ready cDNA inserts, VIGS can be utilized to screen a large number of genes to determine phenotypes resulting from the knockdown/knockout of gene function. Taking into account the optimal insert design for VIGS, we describe a methodology for producing VIGS-ready cDNA libraries enriched for inserts relevant to the biological process of interest.

  20. Bacterial Cellular Engineering by Genome Editing and Gene Silencing

    Directory of Open Access Journals (Sweden)

    Nobutaka Nakashima

    2014-02-01

    Full Text Available Genome editing is an important technology for bacterial cellular engineering, which is commonly conducted by homologous recombination-based procedures, including gene knockout (disruption, knock-in (insertion, and allelic exchange. In addition, some new recombination-independent approaches have emerged that utilize catalytic RNAs, artificial nucleases, nucleic acid analogs, and peptide nucleic acids. Apart from these methods, which directly modify the genomic structure, an alternative approach is to conditionally modify the gene expression profile at the posttranscriptional level without altering the genomes. This is performed by expressing antisense RNAs to knock down (silence target mRNAs in vivo. This review describes the features and recent advances on methods used in genomic engineering and silencing technologies that are advantageously used for bacterial cellular engineering.

  1. The great silence science and philosophy of Fermi's paradox

    CERN Document Server

    Cirkovic, Milan M

    2018-01-01

    The Great Silence explores the multifaceted problem named after the great Italian physicist Enrico Fermi and his legendary 1950 lunchtime question "Where is everybody?" In many respects, Fermi's paradox is the richest and the most challenging problem for the entire field of astrobiology and the Search for ExtraTerrestrial Intelligence (SETI) studies. This book shows how Fermi's paradox is intricately connected with many fields of learning, technology, arts, and even everyday life. It aims to establish the strongest possible version of the problem, to dispel many related confusions, obfuscations, and prejudices, as well as to offer a novel point of entry to the many solutions proposed in existing literature. Cirkovic argues that any evolutionary worldview cannot avoid resolving the Great Silence problem in one guise or another.

  2. Evaluation of the antagonism of nicotine by mecamylamine and pempidine in the brain

    International Nuclear Information System (INIS)

    Martin, T.J.

    1989-01-01

    Antagonists have been crucial in the characterization of nicotine's pharmacology. Initial evidence for the existence of central nicotinic receptors was based on the fact that nicotine produced a number of behavioral effects that were antagonized by ganglionic blockers that crossed the blood-brain barrier, such as mecamylamine and pempidine. These compounds are thought to be noncompetitive antagonists due to the fact that they do not compete for agonist binding to brain homogenate in vitro. However, pharmacological evidence in support of noncompetitive antagonism is lacking. Dose-response curves for nicotine were determined in the presence of various doses of pempidine for depression of spontaneous activity and antinociception in mice. Pempidine was found to shift the dose response curves for these effects of nicotine in a manner consistent with noncompetitive antagonism. A number of mecamylamine analogs were investigated for antagonism of these central effects of nicotine as well. These studies revealed that the N-, 2-, and 3-methyls were crucial for optimal efficacy and potency and suggests that these compounds possess a specific mechanism of action, possibly involving a receptor. Furthermore, the structure-activity relationships for the mecamylamine analogs were found to be different than that previously reported for the agonists, suggesting that they do not act at the same site. The binding of [ 3 H]-L-nicotine and [ 3 H]-pempidine was studied in vitro to mouse brain homogentate and in situ to rat brain slices. The in situ binding of [ 3 H]-L-nicotine to rat brain slices was quantitated autoradiographically to discrete brain areas in the presence and absence of 1, 10 and 100 μM nicotine and pempidine. Pempidine did not effectively displace [ 3 H]-L-nicotine binding

  3. Relation of arginine-lysine antagonism to herpes simplex growth in tissue culture.

    Science.gov (United States)

    Griffith, R S; DeLong, D C; Nelson, J D

    1981-01-01

    In the studies conducted, arginine deficiency suppressed herpes simplex virus replication in tissue culture. Lysine, an analog of arginine, as an antimetabolite, antagonized the viral growth-promoting action of arginine. The in vitro data may be the basis for the observation that patients prone to herpetic lesions and other related viral infections, particularly during periods of stress, should abstain from arginine excess and may also require supplemental lysine in their diet.

  4. Antagonism between penicillin and erythromycin against Streptococcus pneumoniae in vitro and in vivo

    DEFF Research Database (Denmark)

    Johansen, H K; Jensen, T G; Dessau, R B

    2000-01-01

    The combination of beta-lactam antibiotics and macrolides is often recommended for the initial empirical treatment of acute pneumonia in order to obtain activity against the most important pathogens. Theoretically, this combination may be inexpedient, as the bacteriostatic agent may antagonize...... and in vivo between penicillin and erythromycin suggests that ss-lactam antibiotics and macrolides should not be administered together unless pneumococcal infection is ruled out....

  5. At 1 antagonism and renin inhibition in mice: Pivotal role of targeting angiotensin II in chronic kidney disease

    NARCIS (Netherlands)

    C. Fraune (Christoph); S. Lange (Simon); C. Krebs (Christian); A. Hölzel (Alexandra); J. Baucke (Jana); N. Divac (Nevena); E. Schwedhelm (Edzard); T. Streichert (Thomas); J. Velden (Joachim); I.M. Garrelds (Ingrid); A.H.J. Danser (Jan); A.-R. Frenay (Anne-Roos); H. van Goor (Harry); J.A. Jankowski (Janusz Antoni); R. Stahl (Rolf); G. Nguyen (Genevieve); U. Wenzel (Ulrich)

    2012-01-01

    textabstractThe role of the renin-angiotensin system in chronic kidney disease involves multiple peptides and receptors. Exerting antipodal pathophysiological mechanisms, renin inhibition and AT 1 antagonism ameliorate renal damage. However, it is unclear which mechanism exerts better

  6. Optical silencing of C. elegans cells with arch proton pump.

    Directory of Open Access Journals (Sweden)

    Ayako Okazaki

    Full Text Available BACKGROUND: Optogenetic techniques using light-driven ion channels or ion pumps for controlling excitable cells have greatly facilitated the investigation of nervous systems in vivo. A model organism, C. elegans, with its small transparent body and well-characterized neural circuits, is especially suitable for optogenetic analyses. METHODOLOGY/PRINCIPAL FINDINGS: We describe the application of archaerhodopsin-3 (Arch, a recently reported optical neuronal silencer, to C. elegans. Arch::GFP expressed either in all neurons or body wall muscles of the entire body by means of transgenes were localized, at least partially, to the cell membrane without adverse effects, and caused locomotory paralysis of worms when illuminated by green light (550 nm. Pan-neuronal expression of Arch endowed worms with quick and sustained responsiveness to such light. Worms reliably responded to repeated periods of illumination and non-illumination, and remained paralyzed under continuous illumination for 30 seconds. Worms expressing Arch in different subsets of motor neurons exhibited distinct defects in the locomotory behavior under green light: selective silencing of A-type motor neurons affected backward movement while silencing of B-type motor neurons affected forward movement more severely. Our experiments using a heat-shock-mediated induction system also indicate that Arch becomes fully functional only 12 hours after induction and remains functional for more than 24 hour. CONCLUSIONS/SGNIFICANCE: Arch can be used for silencing neurons and muscles, and may be a useful alternative to currently widely used halorhodopsin (NpHR in optogenetic studies of C. elegans.

  7. Hush… : The Dangers of Silence in Academic Libraries

    Directory of Open Access Journals (Sweden)

    Jessica Schomberg

    2017-04-01

    Full Text Available In Brief This article critiques the idea that civility rhetoric decreases workplace bullying or discrimination. We use Critical Discourse Analysis (CDA to do a rhetorical analysis of a campus-wide civility campaign in contrast with literature about civility in libraries. To combat discrimination and bullying, we need to be attentive to systemic power dynamics and to rhetoric designed to enforce compliance and conformity. We conclude with recommendations about how to raise our voices instead of silencing our peers.

  8. Hypoxia Silences Retrotrapezoid Nucleus Respiratory Chemoreceptors via Alkalosis

    OpenAIRE

    Basting, Tyler M.; Burke, Peter G.R.; Kanbar, Roy; Viar, Kenneth E.; Stornetta, Daniel S.; Stornetta, Ruth L.; Guyenet, Patrice G.

    2015-01-01

    In conscious mammals, hypoxia or hypercapnia stimulates breathing while theoretically exerting opposite effects on central respiratory chemoreceptors (CRCs). We tested this theory by examining how hypoxia and hypercapnia change the activity of the retrotrapezoid nucleus (RTN), a putative CRC and chemoreflex integrator. Archaerhodopsin-(Arch)-transduced RTN neurons were reversibly silenced by light in anesthetized rats. We bilaterally transduced RTN and nearby C1 neurons with Arch (PRSx8-ArchT...

  9. ORGANIZATIONAL SILENCE: SUATU PENGHAMBAT DALAM MEWUJUDKAN KREATIFITAS ORGANISASIONAL

    OpenAIRE

    Berta Bekti Retnawati

    2016-01-01

    There are powerful forces in many organzations that cause widespread withholding of information about potential problems or issues by employess, this collective-level phenomenon as ‘organizational silence’. One significant effect of organizational silence relates to lack of organizational creativity.There are five major organizational factors that enhance creativity in a work environment: organizational climate, leadership style, organizational culture, resources and skills, the structure and...

  10. Developing Gene Silencing for the Study and Treatment of Dystonia

    Science.gov (United States)

    2017-12-01

    that this is possible but using cells growing in a dish in the laboratory, not in living animals. In this project, we aim to answer several specific... important therapeutic implication of these experiments is that either the striatum is not the primary site of dysfunction in DYT1, or that the molecular...1 AWARD NUMBER: W81XWH-14-1-0282 TITLE: Developing Gene Silencing for the Study and Treatment of Dystonia PRINCIPAL INVESTIGATOR: Pedro

  11. Another Piece of the "Silence in PBL" Puzzle: Students' Explanations of Dominance and Quietness as Complementary Group Roles

    Science.gov (United States)

    Skinner, Vicki J.; Braunack-Mayer, Annette; Winning, Tracey A.

    2016-01-01

    A problem-based learning (PBL) assumption is that silence is incompatible with collaborative learning. Although sociocultural studies have reinterpreted silence as collaborative, we must understand how silence occurs in PBL groups. This essay presents students' explanations of dominance, leadership, and silence as PBL group roles. An ethnographic…

  12. Arctigenin antagonizes mineralocorticoid receptor to inhibit the transcription of Na/K-ATPase.

    Science.gov (United States)

    Cheng, Ye; Zhou, Meili; Wang, Yan

    2016-01-01

    Hypertension is one of the most important risk factors in cardiovascular disease and is the most common chronic disease. Mineralocorticoid receptor (MR) antagonists have been successfully used in clinic for the treatment of hypertension. Our study aims to investigate whether Arctigenin can antagonize MR and inhibit the transcription of Na/K-ATPase. The yeast two-hybrid assay was used to screen natural products and Arctigenin was identified as an MR antagonist. The direct binding of Arctigenin to MR was determined using assays based on surface plasmon resonance, differential scanning calorimetry and fluorescence quenching. Furthermore, results from mammalian one-hybrid and transcriptional activation experiments also confirmed that Arctigenin can potently antagonize MR in cells. We demonstrated that Arctigenin can decrease the level of Na/K-ATPase mRNA by antagonizing MR in HK-2 cells. Our findings show that Arctigenin can effectively decrease Na/K-ATPase transcription; thus highlight its potential as an anti-hypertensive drug lead compound. Our current findings demonstrate that Arctigenin is an antagonist of MR and effectively decreases the Na/K-ATPase 1 gene expression. Our work provides a hint for the drug discovery against cardiovascular disease.

  13. Antagonism of Sorafenib and Regorafenib actions by platelet factors in hepatocellular carcinoma cell lines

    International Nuclear Information System (INIS)

    D’Alessandro, Rosalba; Refolo, Maria G; Lippolis, Catia; Giannuzzi, Grazia; Carella, Nicola; Messa, Caterina; Cavallini, Aldo; Carr, Brian I

    2014-01-01

    Platelets are frequently altered in hepatocellular carcinoma (HCC) patients. Platelet lysates (hPL) can enhance HCC cell growth and decrease apoptosis. The aims were to evaluate whether hPL can modulate the actions of Sorafenib or Regorafenib, two clinical HCC multikinase antagonists. Several human HCC cell lines were grown in the presence and absence of Sorafenib or Regorafenib, with or without hPL. Growth was measured by MTT assay, apoptosis was assessed by Annexin V and by western blot, and autophagy and MAPK growth signaling were also measured by western blot, and migration and invasion were measured by standard in vitro assays. Both Sorafenib and Regorafenib-mediated inhibition of cell growth, migration and invasion were all antagonized by hPL. Drug-mediated apoptosis and decrease in phospho-ERK levels were both blocked by hPL, which also increased anti-apoptotic phospho-STAT, Bax and Bcl-xL levels. Preliminary data, obtained with epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I), included in hPL, revealed that these factors were able to antagonized Sorafenib in a proliferation assay, in particular when used in combination. Platelet factors can antagonize Sorafenib or Regorafenib-mediated growth inhibition and apoptosis in HCC cells. The modulation of platelet activity or numbers has the potential to enhance multikinase drug actions

  14. In vitro antagonism of Trichoderma harzianum Rifai against Mycosphaerella fijiensis Morelet

    Directory of Open Access Journals (Sweden)

    Mayra Acosta-Suárez

    2013-10-01

    Full Text Available The in vitro antagonism of Trichoderma harzianum against Mycosphaerella fijiensis, foliar pathogen of banana and plantain, was evaluated. The assays were performed using the dual culture method. Competition for space and nutrients, the antagonistic capacity and forms and intensity of antagonism were determined considering the invasion of the surface of the colony, colonization and sporulation of T. harzianum on M. fijiensis after seven days of inoculation. Finally, the effect of volatile metabolites of T. harzianum was evaluated. The results showed in vitro antagonism of T. harzianum against M. fijiensis by competition for space and nutrients of the culture medium. Trichoderma grew over the pathogen colony with hyperparasitism and high intensity. Also, it completely covered the surface of the culture medium. T. harzianum not inhibited the growth of M. fijiensis by volatile metabolites. Damage was observed in the integrity of the cell wall of M. fijiensis hyphae and the cell content exit. The use of antagonistic fungi, could contribute to the design of strategies for integrated management of this disease. Key words: banana and plantain, biocontrol, mechanisms of action

  15. The Application of Coconut Fiber as Dissipative Silencer

    Science.gov (United States)

    Madlan, M. A.; Ghazali, M. I.; Zaman, I.; Kasron, M. Z.; Ying, T. C.

    2017-01-01

    Heat ventilation air conditioning system (HVAC) is one of the ducting systems that broadly applied in the building. There are HVAC silencers in the market, however the sound absorptive material commonly used is mineral wool. In this research study, a sound absorptive material made of coconut fiber was tested to identify its performance as a potential replacement of green material for ducting silencer. The experiment was carried out in a testing apparatus that follows the BS EN ISO 11691:2009 standard. Different configurations of sound absorptive material and contents of coconut fiber were investigated in the study. The trend of insertion loss at 1/3 octave frequency was identified where at frequency below 3000Hz, the insertion loss of dissipative silencer is observed high at certain frequency with a very narrow range. At 3000Hz, the insertion loss of 4dB to 6dB is constant until 4000Hz and drops until 5000Hz before it increases again steadily up to 13dB at 10000Hz. A similar trend was observed for different configuration of sound absorptive material. Despite the configuration different, the outcome shows that the insertion loss is increasing with higher content of coconut fiber.

  16. Epigenetic silencing of tumor suppressor genes: Paradigms, puzzles, and potential.

    Science.gov (United States)

    Kazanets, Anna; Shorstova, Tatiana; Hilmi, Khalid; Marques, Maud; Witcher, Michael

    2016-04-01

    Cancer constitutes a set of diseases with heterogeneous molecular pathologies. However, there are a number of universal aberrations common to all cancers, one of these being the epigenetic silencing of tumor suppressor genes (TSGs). The silencing of TSGs is thought to be an early, driving event in the oncogenic process. With this in consideration, great efforts have been made to develop small molecules aimed at the restoration of TSGs in order to limit tumor cell proliferation and survival. However, the molecular forces that drive the broad epigenetic reprogramming and transcriptional repression of these genes remain ill-defined. Undoubtedly, understanding the molecular underpinnings of transcriptionally silenced TSGs will aid us in our ability to reactivate these key anti-cancer targets. Here, we describe what we consider to be the five most logical molecular mechanisms that may account for this widely observed phenomenon: 1) ablation of transcription factor binding, 2) overexpression of DNA methyltransferases, 3) disruption of CTCF binding, 4) elevation of EZH2 activity, 5) aberrant expression of long non-coding RNAs. The strengths and weaknesses of each proposed mechanism is highlighted, followed by an overview of clinical efforts to target these processes. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  17. Silencing Deafness: Displacing Disability in the Nineteenth Century

    Directory of Open Access Journals (Sweden)

    Esme Cleall

    2015-03-01

    Full Text Available This article traces the way in which the language of displacement and silence were used in nineteenth-century discussions of deafness and connects this tendency to the marginalised place deaf experience occupies historically. Throughout the nineteenth century, a period which saw the consolidation of ‘the deaf and dumb’ as a social category, the word ‘forgetting’ crept into numerous discussions of deafness by both deaf and hearing commentators. Some, such as the educationalist Alexander Graeme Bell, were overt in their desire to forget deafness, demanding disability was ‘bred out’ and deaf culture condemned to the forgotten past. Others used the term ambivalently and sometimes metaphorically discussing the deaf as ‘forgotten’ by society, and ‘children of silence’. Some even pleaded that people who were deaf were not forgotten. But, though varied, the use of the imagery of forgetting and silence to evoke deafness is recurrent, and may, therefore, be seen to reveal something about how deaf experience can be approached as a displacement where deafness was spatially and imaginatively marginalised. I argue that one of the consequences of the conceptual framing of deafness through the language of forgetting was actively to silence deafness and to neutralise the idea that disability should be marginal and could be forgotten.

  18. Epigenetic silencing of CYP24 in the tumor microenvironment

    Science.gov (United States)

    Johnson, Candace S.; Chung, Ivy; Trump, Donald L.

    2010-01-01

    Calcitriol (1,25 dihydroxycholecalciferol) has significant antitumor activity in vitro and in vivo in a number of tumor model systems. We developed a system for isolation of fresh endothelial cells from tumors and Matrigel environments which demonstrate that CYP24, the catabolic enzyme involved in vitamin D signaling, is epigenetically silenced selectively in tumor-derived endothelial cells (TDEC). TDEC maintain phenotypic characteristics which are distinct from endothelial cells isolated from normal tissues and from Matrigel plugs (MDEC). In TDEC, calcitriol induces G0/G1 arrest, modulates p27 and p21, and induces apoptotic cell death and decreases P-Erk and P-Akt. In contrast, endothelial cells isolated from normal tissues and MDEC are unresponsive to calcitriol-mediated anti-proliferative effects despite intact signaling through the vitamin D receptor (VDR). In TDEC, which is sensitive to calcitriol, the CYP24 promoter is hypermethylated in two CpG island regions located at the 5′end; this hypermethylation may contribute to gene silencing of CYP24. The extent of methylation in these two regions is significantly less in MDEC. Lastly, treatment of TDEC with a DNA methyltransferase inhibitor restores calcitriol-mediated induction of CYP24 and resistance to calcitriol. These data suggest that epigenetic silencing of CYP24 modulates cellular responses to calcitriol. PMID:20304059

  19. s8ORF2 protein of infectious salmon anaemia virus is a RNA-silencing suppressor and interacts with Salmon salar Mov10 (SsMov10) of the host RNAi machinery.

    Science.gov (United States)

    Thukral, Vandana; Varshney, Bhavna; Ramly, Rimatulhana B; Ponia, Sanket S; Mishra, Sumona Karjee; Olsen, Christel M; Banerjea, Akhil C; Mukherjee, Sunil K; Zaidi, Rana; Rimstad, Espen; Lal, Sunil K

    2018-04-01

    The infectious salmon anaemia virus (ISAV) is a piscine virus, a member of Orthomyxoviridae family. It encodes at least 10 proteins from eight negative-strand RNA segments. Since ISAV belongs to the same virus family as Influenza A virus, with similarities in protein functions, they may hence be characterised by analogy. Like NS1 protein of Influenza A virus, s8ORF2 of ISAV is implicated in interferon antagonism and RNA-binding functions. In this study, we investigated the role of s8ORF2 in RNAi suppression in a well-established Agrobacterium transient suppression assay in stably silenced transgenic Nicotiana xanthi. In addition, s8ORF2 was identified as a novel interactor with SsMov10, a key molecule responsible for RISC assembly and maturation in the RNAi pathway. This study thus sheds light on a novel route undertaken by viral proteins in promoting viral growth, using the host RNAi machinery.

  20. The human HECA interacts with cyclins and CDKs to antagonize Wnt-mediated proliferation and chemoresistance of head and neck cancer cells

    International Nuclear Information System (INIS)

    Dowejko, Albert; Bauer, Richard; Bauer, Karin; Müller-Richter, Urs D.A.; Reichert, Torsten E.

    2012-01-01

    There is a growing evidence that the human homologue of the Drosophila headcase (HECA) plays an important role in human carcinogenesis. So far specific protein interaction partners and affected signaling pathways of HECA are still elusive. In a recent study we showed that HECA overexpression in oral squamous-cell carcinoma (OSCC) keratinocytes has tumor suppressive effects resulting in a recuperation of cell cycle control concerning the entry and progression of S-phase, G2- and M-phase. Currently, quantitative RT-PCR and immunohistochemical analysis of primary tumor tissue from OSCC patients demonstrate that HECA expression is markedly decreased compared to normal control patients with abundant HECA expression. Additionally, there is nearly no HECA expression in OSCC metastases. Here, we show that HECA expression is negatively controlled by the Wnt-pathway and TCF4, a Wnt related transcription factor, binds to the HECA promoter. Furthermore, immunocytochemistry reveals colocalization of HECA with the cyclin dependent kinase CDK9. Immunoprecipitation experiments and proximity ligation assays further reveal an interaction of HECA with CDK2, CDK9, Cyclin A and Cyclin K, a direct transcriptional target of the p53 tumor suppressor. Silencing HECA in OSCC cell lines leads to a significant increase of cell division and a markedly increased resistance against the chemotherapeutic cisplatin. On the contrary, HECA overexpressing OSCC cell lines show decreased resistance of OSCC cells against cisplatin. Therefore, HECA could be considered as future therapeutic agent against Wnt-dependent tumor progression. -- Highlights: ► HECA is a new cell cycle regulator with anti-tumor features in head and neck cancer. ► During tumor progression HECA mRNA and protein expression decrease. ► The HECA promotor is a direct target of the Wnt/beta-catenin/TCF-pathway. ► The HECA protein antagonizes Wnt-mediated cell proliferation through interaction with major cell cycle factors.

  1. Multi-gene epigenetic silencing of tumor suppressor genes in T-cell lymphoma cells; delayed expression of the p16 protein upon reversal of the silencing

    DEFF Research Database (Denmark)

    Nagasawa, T; Zhang, Q; Raghunath, P N

    2006-01-01

    )-expressing T-cell lymphomas. p16 gene was epigenetically silenced in all but one of the 10 malignant T-cell lines examined, p15 gene silenced in roughly half of the lines, and p14 was the least frequently affected. Extensive methylation of the p16 promoter was seen in six out of 10 cutaneous T-cell lymphoma...... promoter demethylation and required up to 3 weeks to occur, seemingly reflecting late activation of the p16 gene. These findings indicate that epigenetic silencing affects in T-cell malignancies, often simultaneously, several tumor suppressor genes that impact on key cell functions. The observed...... differential silencing of p16 and p14, and to a lesser degree p15 gene, indicates that the silencing is governed by precise, promoter region-specific mechanisms. The study provides also further rationale for treatment of at least some types of T-cell lymphomas with DNA methyltransferase inhibitors to target...

  2. Kicking against the PRCs - A Domesticated Transposase Antagonises Silencing Mediated by Polycomb Group Proteins and Is an Accessory Component of Polycomb Repressive Complex 2.

    Directory of Open Access Journals (Sweden)

    Shih Chieh Liang

    2015-12-01

    Full Text Available The Polycomb group (PcG and trithorax group (trxG genes play crucial roles in development by regulating expression of homeotic and other genes controlling cell fate. Both groups catalyse modifications of chromatin, particularly histone methylation, leading to epigenetic changes that affect gene activity. The trxG antagonizes the function of PcG genes by activating PcG target genes, and consequently trxG mutants suppress PcG mutant phenotypes. We previously identified the ANTAGONIST OF LIKE HETEROCHROMATIN PROTEIN1 (ALP1 gene as a genetic suppressor of mutants in the Arabidopsis PcG gene LIKE HETEROCHROMATIN PROTEIN1 (LHP1. Here, we show that ALP1 interacts genetically with several other PcG and trxG components and that it antagonizes PcG silencing. Transcriptional profiling reveals that when PcG activity is compromised numerous target genes are hyper-activated in seedlings and that in most cases this requires ALP1. Furthermore, when PcG activity is present ALP1 is needed for full activation of several floral homeotic genes that are repressed by the PcG. Strikingly, ALP1 does not encode a known chromatin protein but rather a protein related to PIF/Harbinger class transposases. Phylogenetic analysis indicates that ALP1 is broadly conserved in land plants and likely lost transposase activity and acquired a novel function during angiosperm evolution. Consistent with this, immunoprecipitation and mass spectrometry (IP-MS show that ALP1 associates, in vivo, with core components of POLYCOMB REPRESSIVE COMPLEX 2 (PRC2, a widely conserved PcG protein complex which functions as a H3K27me3 histone methyltransferase. Furthermore, in reciprocal pulldowns using the histone methyltransferase CURLY LEAF (CLF, we identify not only ALP1 and the core PRC2 components but also plant-specific accessory components including EMBRYONIC FLOWER 1 (EMF1, a transcriptional repressor previously associated with PRC1-like complexes. Taken together our data suggest that ALP1

  3. Kicking against the PRCs - A Domesticated Transposase Antagonises Silencing Mediated by Polycomb Group Proteins and Is an Accessory Component of Polycomb Repressive Complex 2.

    Science.gov (United States)

    Liang, Shih Chieh; Hartwig, Ben; Perera, Pumi; Mora-García, Santiago; de Leau, Erica; Thornton, Harry; de Lima Alves, Flavia; de Alves, Flavia Lima; Rappsilber, Juri; Rapsilber, Juri; Yang, Suxin; James, Geo Velikkakam; Schneeberger, Korbinian; Finnegan, E Jean; Turck, Franziska; Goodrich, Justin

    2015-12-01

    The Polycomb group (PcG) and trithorax group (trxG) genes play crucial roles in development by regulating expression of homeotic and other genes controlling cell fate. Both groups catalyse modifications of chromatin, particularly histone methylation, leading to epigenetic changes that affect gene activity. The trxG antagonizes the function of PcG genes by activating PcG target genes, and consequently trxG mutants suppress PcG mutant phenotypes. We previously identified the ANTAGONIST OF LIKE HETEROCHROMATIN PROTEIN1 (ALP1) gene as a genetic suppressor of mutants in the Arabidopsis PcG gene LIKE HETEROCHROMATIN PROTEIN1 (LHP1). Here, we show that ALP1 interacts genetically with several other PcG and trxG components and that it antagonizes PcG silencing. Transcriptional profiling reveals that when PcG activity is compromised numerous target genes are hyper-activated in seedlings and that in most cases this requires ALP1. Furthermore, when PcG activity is present ALP1 is needed for full activation of several floral homeotic genes that are repressed by the PcG. Strikingly, ALP1 does not encode a known chromatin protein but rather a protein related to PIF/Harbinger class transposases. Phylogenetic analysis indicates that ALP1 is broadly conserved in land plants and likely lost transposase activity and acquired a novel function during angiosperm evolution. Consistent with this, immunoprecipitation and mass spectrometry (IP-MS) show that ALP1 associates, in vivo, with core components of POLYCOMB REPRESSIVE COMPLEX 2 (PRC2), a widely conserved PcG protein complex which functions as a H3K27me3 histone methyltransferase. Furthermore, in reciprocal pulldowns using the histone methyltransferase CURLY LEAF (CLF), we identify not only ALP1 and the core PRC2 components but also plant-specific accessory components including EMBRYONIC FLOWER 1 (EMF1), a transcriptional repressor previously associated with PRC1-like complexes. Taken together our data suggest that ALP1 inhibits Pc

  4. Technical advances in trigger-induced RNA interference gene silencing in the parasite Entamoeba histolytica.

    Science.gov (United States)

    Khalil, Mohamed I; Foda, Bardees M; Suresh, Susmitha; Singh, Upinder

    2016-03-01

    Entamoeba histolytica has a robust endogenous RNA interference (RNAi) pathway. There are abundant 27 nucleotide (nt) anti-sense small RNAs (AS sRNAs) that target genes for silencing and the genome encodes many genes involved in the RNAi pathway such as Argonaute proteins. Importantly, an E. histolytica gene with numerous AS sRNAs can function as a "trigger" to induce silencing of a gene that is fused to the trigger. Thus, the amebic RNAi pathway regulates gene expression relevant to amebic biology and has additionally been harnessed as a tool for genetic manipulation. In this study we have further improved the trigger-induced gene silencing method. We demonstrate that rather than using the full-length gene, a short portion of the coding region fused to a trigger is sufficient to induce silencing; the first 537 bp of the E. histolytica rhomboid gene (EhROM1) fused in-frame to the trigger was sufficient to silence EhROM1. We also demonstrated that the trigger method could silence two amebic genes concomitantly; fusion of the coding regions of EhROM1 and transcription factor, EhMyb, in-frame to a trigger gene resulted in both genes being silenced. Alternatively, two genes can be silenced sequentially: EhROM1-silenced parasites with no drug selection plasmid were transfected with trigger-EhMyb, resulting in parasites with both EhROM1 and EhMyb silenced. With all approaches tested, the trigger-mediated silencing was substantive and silencing was maintained despite loss of the G418 selectable marker. All gene silencing was associated with generation of AS sRNAs to the silenced gene. We tested the reversibility of the trigger system using inhibitors of histone modifications but found that the silencing was highly stable. This work represents a technical advance in the trigger gene silencing method in E. histolytica. Approaches that readily silence multiple genes add significantly to the genetic toolkit available to the ameba research community. Copyright © 2016

  5. Recent patents in RNA silencing in plants: constructs, methods and applications in plant biotechnology.

    Science.gov (United States)

    López-Gomollón, Sara; Dalmay, Tamas

    2010-11-01

    RNA silencing is a recently discovered mechanism to regulate gene expression at transcriptional and posttranscriptional levels. It is based on the recognition and methylation of target genes or cleavage of target mRNAs by small RNA molecules, with length varying from 21 to 24 nucleotides. RNA silencing plays an important role modulating most of the important cell processes, such as growth, development or stress response. During the past few years, diverse strategies have been applied to exploit RNA silencing as a tool to create plants with enhanced economical properties or able to cope with pathogens or abiotic stress. This review describes the most important patents related to RNA silencing in plants, which disclose vectors designed to induce RNA silencing by hairpin RNAs, amplicons or virus-based plasmids, methods for detection and quantification of silencing as well as general uses in plant biotechnology.

  6. Lactate dehydrogenase A silencing in IDH mutant gliomas.

    Science.gov (United States)

    Chesnelong, Charles; Chaumeil, Myriam M; Blough, Michael D; Al-Najjar, Mohammad; Stechishin, Owen D; Chan, Jennifer A; Pieper, Russell O; Ronen, Sabrina M; Weiss, Samuel; Luchman, H Artee; Cairncross, J Gregory

    2014-05-01

    Mutations of the isocitrate dehydrogenase 1 and 2 gene (IDH1/2) were initially thought to enhance cancer cell survival and proliferation by promoting the Warburg effect. However, recent experimental data have shown that production of 2-hydroxyglutarate by IDH mutant cells promotes hypoxia-inducible factor (HIF)1α degradation and, by doing so, may have unexpected metabolic effects. We used human glioma tissues and derived brain tumor stem cells (BTSCs) to study the expression of HIF1α target genes in IDH mutant ((mt)) and IDH wild-type ((wt)) tumors. Focusing thereafter on the major glycolytic enzyme, lactate dehydrogenase A (LDHA), we used standard molecular methods and pyrosequencing-based DNA methylation analysis to identify mechanisms by which LDHA expression was regulated in human gliomas. We found that HIF1α-responsive genes, including many essential for glycolysis (SLC2A1, PDK1, LDHA, SLC16A3), were underexpressed in IDH(mt) gliomas and/or derived BTSCs. We then demonstrated that LDHA was silenced in IDH(mt) derived BTSCs, including those that did not retain the mutant IDH1 allele (mIDH(wt)), matched BTSC xenografts, and parental glioma tissues. Silencing of LDHA was associated with increased methylation of the LDHA promoter, as was ectopic expression of mutant IDH1 in immortalized human astrocytes. Furthermore, in a search of The Cancer Genome Atlas, we found low expression and high methylation of LDHA in IDH(mt) glioblastomas. To our knowledge, this is the first demonstration of downregulation of LDHA in cancer. Although unexpected findings, silencing of LDHA and downregulation of several other glycolysis essential genes raise the intriguing possibility that IDH(mt) gliomas have limited glycolytic capacity, which may contribute to their slow growth and better prognosis.

  7. Exon silencing by UAGG motifs in response to neuronal excitation.

    Directory of Open Access Journals (Sweden)

    Ping An

    2007-02-01

    Full Text Available Alternative pre-mRNA splicing plays fundamental roles in neurons by generating functional diversity in proteins associated with the communication and connectivity of the synapse. The CI cassette of the NMDA R1 receptor is one of a variety of exons that show an increase in exon skipping in response to cell excitation, but the molecular nature of this splicing responsiveness is not yet understood. Here we investigate the molecular basis for the induced changes in splicing of the CI cassette exon in primary rat cortical cultures in response to KCl-induced depolarization using an expression assay with a tight neuron-specific readout. In this system, exon silencing in response to neuronal excitation was mediated by multiple UAGG-type silencing motifs, and transfer of the motifs to a constitutive exon conferred a similar responsiveness by gain of function. Biochemical analysis of protein binding to UAGG motifs in extracts prepared from treated and mock-treated cortical cultures showed an increase in nuclear hnRNP A1-RNA binding activity in parallel with excitation. Evidence for the role of the NMDA receptor and calcium signaling in the induced splicing response was shown by the use of specific antagonists, as well as cell-permeable inhibitors of signaling pathways. Finally, a wider role for exon-skipping responsiveness is shown to involve additional exons with UAGG-related silencing motifs, and transcripts involved in synaptic functions. These results suggest that, at the post-transcriptional level, excitable exons such as the CI cassette may be involved in strategies by which neurons mount adaptive responses to hyperstimulation.

  8. Epigenetic silencing may aid evolution by gene duplication.

    Science.gov (United States)

    Rodin, Sergei N; Riggs, Arthur D

    2003-06-01

    Gene duplication is commonly regarded as the main evolutionary path toward the gain of a new function. However, even with gene duplication, there is a loss-versus-gain dilemma: most newly born duplicates degrade to pseudogenes, since degenerative mutations are much more frequent than advantageous ones. Thus, something additional seems to be needed to shift the loss versus gain equilibrium toward functional divergence. We suggest that epigenetic silencing of duplicates might play this role in evolution. This study began when we noticed in a previous publication (Lynch M, Conery JS [2000] Science 291:1151-1155) that the frequency of functional young gene duplicates is higher in organisms that have cytosine methylation (H. sapiens, M. musculus, and A. thaliana) than in organisms that do not have methylated genomes (S. cerevisiae, D. melanogaster, and C. elegans). We find that genome data analysis confirms the likelihood of much more efficient functional divergence of gene duplicates in mammals and plants than in yeast, nematode, and fly. We have also extended the classic model of gene duplication, in which newly duplicated genes have exactly the same expression pattern, to the case when they are epigenetically silenced in a tissue- and/or developmental stage-complementary manner. This exposes each of the duplicates to negative selection, thus protecting from "pseudogenization." Our analysis indicates that this kind of silencing (i) enhances evolution of duplicated genes to new functions, particularly in small populations, (ii) is quite consistent with the subfunctionalization model when degenerative but complementary mutations affect different subfunctions of the gene, and (iii) furthermore, may actually cooperate with the DDC (duplication-degeneration-complementation) process.

  9. DNA methylation, genomic silencing, and links to nutrition and cancer.

    Science.gov (United States)

    McCabe, Dale C; Caudill, Marie A

    2005-06-01

    DNA methylation is a heritable epigenetic feature that is associated with transcriptional silencing, X-chromosome inactivation, genetic imprinting, and genomic stability. The addition of the methyl group is catalyzed by a family of DNA methyltransferases whose co-substrates are DNA and S-adenosylmethionine, the latter being derived from the methionine cycle. Aberrant DNA methylation is linked to numerous pathologies, including cancer. The purpose of this review is to describe DNA methylation and its functions, to examine the relationship between dietary methyl insufficiency and DNA methylation, and to evaluate the associations between DNA methylation and cancer.

  10. Silent God in a Wordy World. Silence in Ignatian Spirituality

    OpenAIRE

    García de Castro Valdés, S.J., José

    2016-01-01

    The Society of Jesus is an apostolic religious order involved in many different activities and missions. Jesuits live far away from monasteries and strict contemplative life. Nevertheless, one of the most well-known peculiarities of the Ignatian Spiritual Exercises is that a complete and absolute silence is required during the time of the retreat. Where and how should we place “silence” in the life of an Ignatian spiritual and mystical experience?

  11. Surface functionalisation of PLGA nanoparticles for gene silencing

    DEFF Research Database (Denmark)

    Andersen, Morten Østergaard; Lichawska, Agata; Arpanaei, Ayyoob

    2010-01-01

    . In addition, particles containing cetylated-PEI achieved 64% silencing of TNFα in J774.1 cells. This rapid method for surface modification of PLGA nanoparticles promotes its application for alternative cetylated functional derivatives as a strategy to control specific biological properties of nanoparticles.......This work presents a method for decorating the surface of poly (lactide-co-glycolide) (PLGA) nanoparticles with polyethyleneimine (PEI) utilising a cetyl derivative to improve surface functionalisation and siRNA delivery. Sub-micron particles were produced by an emulsion-diffusion method using...

  12. Nuclear architecture and gene silencing in olfactory sensory neurons.

    Science.gov (United States)

    Armelin-Correa, Lucia M; Nagai, Maíra H; Leme Silva, Artur G; Malnic, Bettina

    2014-01-01

    Odorants are discriminated by hundreds of odorant receptor (OR) genes, which are dispersed throughout the mammalian genome. The OR genes are expressed in a highly specialized type of cell, the olfactory sensory neuron. Each one of these neurons expresses one of the 2 alleles from one single OR gene type. The mechanisms underlying OR gene expression are unclear. Here we describe recent work demonstrating that the olfactory sensory neuron shows a particular nuclear architecture, and that the genomic OR loci are colocalized in silencing heterochromatin compartments within the nucleus. These discoveries highlight the important role played by epigenetic modifications and nuclear genome organization in the regulation of OR gene expression.

  13. Antagonism of a (+)N-allylnormetazocine stimulus by (-)PPAP and several structurally related analogs.

    Science.gov (United States)

    Glennon, R A; Young, R; Herndon, J L

    1993-08-01

    Employing rats trained to discriminate 5 mg/kg of the benzomorphan opioid (+)N-allylnormetazocine [(+)NANM] from vehicle, tests of stimulus generalization and antagonism were conducted to determine the influence of several potential sigma-receptor ligands. It has been previously suggested that the (+)NANM stimulus may involve concurrent action at sigma- and phencyclidine (PCP) receptors. Although the low-affinity sigma-antagonist rimcazole was without stimulus-attenuating effect, three novel sigma-ligands--(-)PPAP, CNS 3018, and CNS 3093 (ID50 doses = 3.2, 6.7, and 4.5 mg/kg, respectively)--antagonized the (+)NANM stimulus in a dose-related fashion. The nonselective serotonergic agent 1-(3-trifluoromethyl)phenylpiperazine (TFMPP) produced partial generalization in (+)NANM-trained animals whereas buspirone, a 5-hydroxytryptamine1A (5-HT1A) agonist, attenuated (to 27% drug-appropriate responding) the (+)NANM stimulus. Because the prototypic 5-HT1A agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) failed to attenuate the (+)NANM stimulus at pharmacologically relevant doses, it seems unlikely that the (+)NANM stimulus involves a 5-HT1A mechanism. TFMPP and buspirone display modest affinity for sigma-receptors and this may account for the present findings with these agents. The present results neither establish a role for sigma involvement in the stimulus properties of (+)NANM nor eliminate a role for PCP receptors. They do, however, demonstrate that sigma-ligands with little to no affinity for PCP receptors are capable of antagonizing the (+)NANM stimulus.

  14. Alcohol-Induced Impairment of Balance is Antagonized by Energy Drinks.

    Science.gov (United States)

    Marczinski, Cecile A; Fillmore, Mark T; Stamates, Amy L; Maloney, Sarah F

    2018-01-01

    The acute administration of alcohol reliably impairs balance and motor coordination. While it is common for consumers to ingest alcohol with other stimulant drugs (e.g., caffeine, nicotine), little is known whether prototypical alcohol-induced balance impairments are altered by stimulant drugs. The purpose of this study was to examine whether the coadministration of a high-caffeine energy drink with alcohol can antagonize expected alcohol-induced increases in body sway. Sixteen social drinkers (of equal gender) participated in 4 separate double-blind dose administration sessions that involved consumption of alcohol and energy drinks, alone and in combination. Following dose administration, participants completed automated assessments of balance stability (both eyes open and eyes closed) measured using the Biosway Portable Balance System. Participants completed several subjective measures including self-reported ratings of sedation, stimulation, fatigue, and impairment. Blood pressure and pulse rate were recorded repeatedly. The acute administration of alcohol increased body sway, and the coadministration of energy drinks antagonized this impairment. When participants closed their eyes, alcohol-induced body sway was similar whether or not energy drinks were ingested. While alcohol administration increased ratings of sedation and fatigue, energy drink administration increased ratings of stimulation and reduced ratings of fatigue. Modest increases in systolic and diastolic blood pressure following energy drink administration were also observed. Visual assessment of balance impairment is frequently used to indicate that an individual has consumed too much alcohol (e.g., as part of police-standardized field sobriety testing or by a bartender assessing when someone should no longer be served more alcohol). The current findings suggest that energy drinks can antagonize alcohol-induced increases in body sway, indicating that future work is needed to determine whether this

  15. Azithromycin May Antagonize Inhaled Tobramycin When Targeting Pseudomonas aeruginosa in Cystic Fibrosis

    Science.gov (United States)

    Nick, Jerry A.; Moskowitz, Samuel M.; Chmiel, James F.; Forssén, Anna V.; Kim, Sun Ho; Saavedra, Milene T.; Saiman, Lisa; Taylor-Cousar, Jennifer L.

    2014-01-01

    Rationale: Recent studies of inhaled tobramycin in subjects with cystic fibrosis (CF) find less clinical improvement than previously observed. Nonhuman data suggest that in some strains of Pseudomonas aeruginosa, azithromycin can antagonize tobramycin. Objectives: We tested the hypothesis that concomitant azithromycin use correlates with less improvement in key outcome measures in subjects receiving inhaled tobramycin while not affecting those receiving a comparative, nonaminoglycoside inhaled antibiotic. Methods: We studied a cohort of 263 subjects with CF enrolled in a recent clinical trial comparing inhaled tobramycin with aztreonam lysine. We performed a secondary analysis to examine key clinical and microbiologic outcomes based on concomitant, chronic azithromycin use at enrollment. Measurements and Main Results: The cohort randomized to inhaled tobramycin and reporting azithromycin use showed a significant decrease in the percent predicted FEV1 after one and three courses of inhaled tobramycin when compared with those not reporting azithromycin use (28 d: −0.51 vs. 3.43%, P azithromycin and inhaled tobramycin use was also associated with earlier need for additional antibiotics, lesser improvement in disease-related quality of life, and a trend toward less reduction in sputum P. aeruginosa density. Subjects randomized to inhaled aztreonam lysine had significantly greater improvement in these outcome measures, which were unaffected by concomitant azithromycin use. Outcomes in those not using azithromycin who received inhaled tobramycin were not significantly different from subjects receiving aztreonam lysine. Azithromycin also antagonized tobramycin but not aztreonam lysine in 40% of P. aeruginosa clinical isolates tested in vitro. Conclusions: Oral azithromycin may antagonize the therapeutic benefits of inhaled tobramycin in subjects with CF with P. aeruginosa airway infection. PMID:24476418

  16. Logic of two antagonizing intra-species quorum sensing systems in bacteria.

    Science.gov (United States)

    Prajapat, Mahendra Kumar; Saini, Supreet

    2018-03-01

    Bacteria release signaling molecules into the surrounding environment and sense them when present in their proximity. Using this strategy, a cell estimates the number of neighbors in its surrounding. Upon sensing a critical number of individuals, bacteria coordinate a number of cellular processes. This density-dependent control of gene expression and physiology is called quorum sensing (QS). Quorum sensing controls a wide variety of functions in bacteria, including those related to motility, growth, virulence etc. Quorum sensing has been widely observed in bacteria while the individuals of the same species or different species compete and cooperate each other. Interestingly, many species possess more than one QS system (intra-species) and these QS systems interact each other to perform quorum sensing. Thus, several logical arrangements can be possible based on the interaction among intra-species QS systems - parallel, series, antagonizing, and agonizing. In this work, we perform simulations to understand the logic of interaction between two antagonizing intra-species QS systems. In such an interaction, one QS system gets fully expressed and the other only gets partially expressed. This is found to be dictated by the interplay between autoinducer's diffusivity and antagonizing strength. In addition, we speculate an important role of the intracellular regulators (eg. LuxR) in maintaining the uniform response among the individual cells from the different localities. We also expect the interplay between the autoinducer's diffusivity and distribution of cells in fine tuning the collective response. Interestingly, in a localized niche with a heterogeneous cell distribution, the cells are expected to perform a global quorum sensing via fully expressed QS system and a local quorum sensing via partially expressed QS system. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. ANTAGONISM OF PROGESTERONE RECEPTOR SUPPRESSES CAROTID BODY RESPONSES TO HYPOXIA AND NICOTINE IN RAT PUPS

    OpenAIRE

    JOSEPH, V.; NIANE, L. M.; BAIRAM, A.

    2012-01-01

    We tested the hypothesis that antagonism of progesterone receptor (PR) in newborn rats alters carotid body and respiratory responses to hypoxia and nicotinic receptor agonists. Rats were treated with the PR antagonist mifepristone (daily oral gavage 40 μg/g/d) or vehicle between post-natal days 3 and 15. In 11–14-day-old rats, we used in vitro carotid body/carotid sinus nerve preparation and whole body plethysmography to assess the carotid body and ventilatory responses to hypoxia (65 mmHg in...

  18. Antagonism between penicillin and erythromycin against Streptococcus pneumoniae in vitro and in vivo

    DEFF Research Database (Denmark)

    Johansen, H K; Jensen, T G; Dessau, R B

    2000-01-01

    The combination of beta-lactam antibiotics and macrolides is often recommended for the initial empirical treatment of acute pneumonia in order to obtain activity against the most important pathogens. Theoretically, this combination may be inexpedient, as the bacteriostatic agent may antagonize...... the effect of the bactericidal agent. In this study, the possible interaction between penicillin and erythromycin was investigated in vitro and in vivo against four clinical isolates of Streptococcus pneumoniae with MICs of penicillin ranging from 0.016 to 0.5 mg/L and of erythromycin from 0. 25 to >128 mg...

  19. Antagonism of Bacillus subtilis strain AG1 against vine wood fungal pathogens

    Directory of Open Access Journals (Sweden)

    A. Alfonzo

    2009-05-01

    Full Text Available Antagonistic substances produced by a Bacillus subtilis strain (AG1, which were previously found to slow down the growth of esca fungi in vitro, were produced in an artificial medium, isolated from the cell-free medium by precipitation and acidification (to less than pH 2.5 and extracted from the precipitate with 96% ethanol. The crude extract employed in antibiotic assays confirmed, in vitro, the antagonism of B. subtilis against Phaeoacremonium aleophilum and Phaeomoniella chlamydospora, and also showed an antifungal activity toward Verticillium dahliae and Botryosphaeria rhodina.

  20. Surface proteins from Lactobacillus kefir antagonize in vitro cytotoxic effect of Clostridium difficile toxins.

    Science.gov (United States)

    Carasi, Paula; Trejo, Fernando M; Pérez, Pablo F; De Antoni, Graciela L; Serradell, María de los Angeles

    2012-02-01

    In this work, the ability of S-layer proteins from kefir-isolated Lactobacillus kefir strains to antagonize the cytophatic effects of toxins from Clostridium difficile (TcdA and TcdB) on eukaryotic cells in vitro was tested by cell detachment assay. S-layer proteins from eight different L. kefir strains were able to inhibit the damage induced by C. difficile spent culture supernatant to Vero cells. Besides, same protective effect was observed by F-actin network staining. S-layer proteins from aggregating L. kefir strains (CIDCA 83115, 8321, 8345 and 8348) showed a higher inhibitory ability than those belonging to non-aggregating ones (CIDCA 83111, 83113, JCM 5818 and ATCC 8007), suggesting that differences in the structure could be related to the ability to antagonize the effect of clostridial toxins. Similar results were obtained using purified TcdA and TcdB. Protective effect was not affected by proteases inhibitors or heat treatment, thus indicating that proteolytic activity is not involved. Only preincubation with specific anti-S-layer antibodies significantly reduced the inhibitory effect of S-layer proteins, suggesting that this could be attributed to a direct interaction between clostridial toxins and L. kefir S-layer protein. Interestingly, the interaction of toxins with S-layer carrying bacteria was observed by dot blot and fluorescence microscopy with specific anti-TcdA or anti-TcdB antibodies, although L. kefir cells did not show protective effects. We hypothesize that the interaction between clostridial toxins and soluble S-layer molecules is different from the interaction with S-layer on the surface of the bacteria thus leading a different ability to antagonize cytotoxic effect. This is the first report showing the ability of S-layer proteins from kefir lactobacilli to antagonize biological effects of bacterial toxins. These results encourage further research on the role of bacterial surface molecules to the probiotic properties of L. kefir and could

  1. An effector of the Irish potato famine pathogen antagonizes a host autophagy cargo receptor

    Science.gov (United States)

    Dagdas, Yasin F; Belhaj, Khaoula; Maqbool, Abbas; Chaparro-Garcia, Angela; Pandey, Pooja; Petre, Benjamin; Tabassum, Nadra; Cruz-Mireles, Neftaly; Hughes, Richard K; Sklenar, Jan; Win, Joe; Menke, Frank; Findlay, Kim; Banfield, Mark J; Kamoun, Sophien; Bozkurt, Tolga O

    2016-01-01

    Plants use autophagy to safeguard against infectious diseases. However, how plant pathogens interfere with autophagy-related processes is unknown. Here, we show that PexRD54, an effector from the Irish potato famine pathogen Phytophthora infestans, binds host autophagy protein ATG8CL to stimulate autophagosome formation. PexRD54 depletes the autophagy cargo receptor Joka2 out of ATG8CL complexes and interferes with Joka2's positive effect on pathogen defense. Thus, a plant pathogen effector has evolved to antagonize a host autophagy cargo receptor to counteract host defenses. DOI: http://dx.doi.org/10.7554/eLife.10856.001 PMID:26765567

  2. Bacterial Seed Endophytes of Domesticated Cucurbits Antagonize Fungal and Oomycete Pathogens Including Powdery Mildew

    Directory of Open Access Journals (Sweden)

    Eman M. Khalaf

    2018-02-01

    Full Text Available The cucurbit vegetables, including cucumbers, melons and pumpkins, have been cultivated for thousands of years without fungicides. However, their seed germination stage is prone to be infected by soil-borne fungal and oomycete pathogens. Endophytes are symbionts that reside inside plant tissues including seeds. Seed endophytes are founders of the juvenile plant microbiome and can promote host defense at seed germination and later stages. We previously isolated 169 bacterial endophytes associated with seeds of diverse cultivated cucurbits. We hypothesized that these endophytes can antagonize major fungal and oomycete pathogens. Here we tested the endophytes for in vitro antagonism (dual culture assays against important soil-borne pathogens (Rhizoctonia solani, Fusarium graminearum, Phytophthora capsici, Pythium aphanideratum. The endophytes were also assayed in planta (leaf disk and detached leaf bioassays for antagonism against a foliar pathogen of global importance, Podosphaera fuliginea, the causative agent of cucurbit powdery mildew. The endophytes were further tested in vitro for secretion of volatile organic compounds (VOCs known to induce plant defense. Extracellular ribonuclease activity was also tested, as a subset of pathogenesis-related (PR proteins of plant hosts implicated in suppression of fungal pathogens, displays ribonuclease activity. An unexpected majority of the endophytes (70%, 118/169 exhibited antagonism to the five phytopathogens, of which 68% (50/73 of in vitro antagonists belong to the genera Bacillus and Paenibacillus. All Lactococcus and Pantoea endophytes exhibited anti-oomycete activity. However, amongst the most effective inoculants against Podosphaera fuliginea were Pediococcus and Pantoea endophytes. Interestingly, 67% (113/169 of endophytes emitted host defense inducing VOCs (acetoin/diacetyl and 62% (104/169 secreted extracellular ribonucleases in vitro, respectively. These results show that seeds of cultivated

  3. Disruption of Cell-to-Cell Signaling Does Not Abolish the Antagonism of Phaeobacter gallaeciensis toward the Fish Pathogen Vibrio anguillarum in Algal Systems

    DEFF Research Database (Denmark)

    Prol García, María Jesús; D'Alvise, Paul; Gram, Lone

    2013-01-01

    Quorum sensing (QS) regulates Phaeobacter gallaeciensis antagonism in broth systems; however, we demonstrate here that QS is not important for antagonism in algal cultures. QS mutants reduced Vibrio anguillarum to the same extent as the wild type. Consequently, a combination of probiotic Phaeobac......Quorum sensing (QS) regulates Phaeobacter gallaeciensis antagonism in broth systems; however, we demonstrate here that QS is not important for antagonism in algal cultures. QS mutants reduced Vibrio anguillarum to the same extent as the wild type. Consequently, a combination of probiotic...

  4. Protein deprivation decreases male survival and the intensity of sexual antagonism in southern field crickets Gryllus bimaculatus.

    Science.gov (United States)

    Han, C S; Dingemanse, N J

    2017-04-01

    Recent theory predicts that the magnitude of sexual antagonism should depend on how well populations are adapted to their environment. We tested this idea experimentally by comparing intersexual genetic correlations for adult survival in pedigreed populations of southern field crickets (Gryllus bimaculatus) raised on naturally balanced (free-choice) vs. imbalanced (protein-deprived) diets. We tested for (1) sex differences in nutritional intake and preference, (2) sex-specific effects of protein deprivation on survival and (3) diet dependence of the level of sexual antagonism. Adult males and females consumed a similar amount of protein, but protein deprivation decreased male survival but not female survival. Protein deprivation appeared to decrease the degree of sexual antagonism as intersexual genetic correlations were significantly lower than 1 only for the complementary free-choice diet group but close to 1 for the protein-deficient diet group. Our findings thereby implied that variation in nutritional environments can alter the magnitude of sexual antagonism. This research represents an important step towards understanding the relationship between sexual antagonism and adaptation in heterogeneous environments. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

  5. Experimental testing of Mackay's model for functional antagonism in the isolated costo-uterus of the rat.

    Science.gov (United States)

    Henry, P. J.; Lulich, K. M.; Paterson, J. W.

    1985-01-01

    Several key predictions of a recently developed model for functional antagonism (Mackay, 1981) were experimentally tested using the rat isolated costo-uterine preparation. In the presence of the functional antagonist fenoterol (Fen), the functional constants (KAF) for carbachol and oxotremorine (Oxo) were respectively 9.9 and 3.4 fold greater than their corresponding affinity constants (KA). According to Mackay's model for functional antagonism, the higher KAF/KA ratio for carbachol indicates that this cholinoceptor agonist has a greater efficacy than Oxo. This was confirmed by using conventional pharmacological methods. As predicted from the model of functional antagonism, the plot of KAF/KA-1 against the fraction of cholinoceptors not irreversibly blocked by phenoxybenzamine (Pbz) was linear for both carbachol and Oxo and the lines of best fit crossed the axes at a point not significantly different from the origin. The value of 4.6 for the relative efficacy of carbachol to Oxo estimated from functional antagonism studies was comparable to the value of 5.6 calculated using the method of irreversible antagonism proposed by Furchgott (1966). PMID:3840396

  6. Sexuality and 'silence' among Khasi youth of Meghalaya, Northeast India.

    Science.gov (United States)

    War, Ryntihlin Jennifer; Albert, Sandra

    2013-01-01

    The importance of sex education has been well documented in the literature, but there exists a lack of research involving indigenous youth in India. This paper describes perceptions, knowledge and attitudes towards sex education, sexuality, pre-marital sex, rape and homosexuality among indigenous students from the matrilineal Khasi tribe attending a university in Meghalaya in northeast India. Qualitative and quantitative data were collected during and after reproductive health, sexuality and life skills courses. Despite the impression of sexual permissiveness of indigenous peoples that exists in India, students reported a societal silence on issues related to sexuality. Lack of appropriate words in the indigenous language potentially contributes to this silence. Although co-habitation is common and culturally acceptable, students disapproved of pre-marital sex. The influence of Christianisation was also perceived in the frequent reference to sin and guilt associated with masturbation, homosexuality, pre-marital sex and abortion. Students reported that the sex education received in school was 'childish' and inadequate for their adult needs. Many had unrealistic images of what constituted 'normal' sex and also blamed women for rape. The majority of indigenous students expressed the need for non-judgmental fora for discussions on sexual health and for sexuality education.

  7. ABCE1 is a highly conserved RNA silencing suppressor.

    Directory of Open Access Journals (Sweden)

    Kairi Kärblane

    Full Text Available ATP-binding cassette sub-family E member 1 (ABCE1 is a highly conserved protein among eukaryotes and archaea. Recent studies have identified ABCE1 as a ribosome-recycling factor important for translation termination in mammalian cells, yeast and also archaea. Here we report another conserved function of ABCE1. We have previously described AtRLI2, the homolog of ABCE1 in the plant Arabidopsis thaliana, as an endogenous suppressor of RNA silencing. In this study we show that this function is conserved: human ABCE1 is able to suppress RNA silencing in Nicotiana benthamiana plants, in mammalian HEK293 cells and in the worm Caenorhabditis elegans. Using co-immunoprecipitation and mass spectrometry, we found a number of potential ABCE1-interacting proteins that might support its function as an endogenous suppressor of RNA interference. The interactor candidates are associated with epigenetic regulation, transcription, RNA processing and mRNA surveillance. In addition, one of the identified proteins is translin, which together with its binding partner TRAX supports RNA interference.

  8. Epigenetic silencing of serine protease HTRA1 drives polyploidy

    International Nuclear Information System (INIS)

    Schmidt, Nina; Irle, Inga; Ripkens, Kamilla; Lux, Vanda; Nelles, Jasmin; Johannes, Christian; Parry, Lee; Greenow, Kirsty; Amir, Sarah; Campioni, Mara; Baldi, Alfonso; Oka, Chio; Kawaichi, Masashi; Clarke, Alan R.; Ehrmann, Michael

    2016-01-01

    Increased numbers and improperly positioned centrosomes, aneuploidy or polyploidy, and chromosomal instability are frequently observed characteristics of cancer cells. While some aspects of these events and the checkpoint mechanisms are well studied, not all players have yet been identified. As the role of proteases other than the proteasome in tumorigenesis is an insufficiently addressed question, we investigated the epigenetic control of the widely conserved protease HTRA1 and the phenotypes of deregulation. Mouse embryonal fibroblasts and HCT116 and SW480 cells were used to study the mechanism of epigenetic silencing of HTRA1. In addition, using cell biological and genetic methods, the phenotypes of downregulation of HTRA1 expression were investigated. HTRA1 is epigenetically silenced in HCT116 colon carcinoma cells via the epigenetic adaptor protein MBD2. On the cellular level, HTRA1 depletion causes multiple phenotypes including acceleration of cell growth, centrosome amplification and polyploidy in SW480 colon adenocarcinoma cells as well as in primary mouse embryonic fibroblasts (MEFs). Downregulation of HTRA1 causes a number of phenotypes that are hallmarks of cancer cells suggesting that the methylation state of the HtrA1 promoter may be used as a biomarker for tumour cells or cells at risk of transformation. The online version of this article (doi:10.1186/s12885-016-2425-8) contains supplementary material, which is available to authorized users

  9. Characterization and subcellular localization of an RNA silencing suppressor encoded by Rice stripe tenuivirus

    International Nuclear Information System (INIS)

    Xiong Ruyi; Wu Jianxiang; Zhou Yijun; Zhou Xueping

    2009-01-01

    Rice stripe virus (RSV) is a single-stranded (ss) RNA virus belonging to the genus Tenuivirus. RSV is present in many East Asian countries and causes severe diseases in rice fields, especially in China. In this study, we analyzed six proteins encoded by the virus for their abilities to suppress RNA silencing in plant using a green fluorescent protein (GFP)-based transient expression assay. Our results indicate that NS3 encoded by RSV RNA3, but not other five RSV encoded proteins, can strongly suppress local GFP silencing in agroinfiltrated Nicotiana benthamiana leaves. NS3 can reverse the GFP silencing, it can also prevent long distance spread of silencing signals which have been reported to be necessary for inducing systemic silencing in host plants. The NS3 protein can significantly reduce the levels of small interfering RNAs (siRNAs) in silencing cells, and was found to bind 21-nucleotide ss-siRNA, siRNA duplex and long ssRNA but not long double-stranded (ds)-RNA. Both N and C terminal of the NS3 protein are critical for silencing suppression, and mutation of the putative nuclear localization signal decreases its local silencing suppression efficiency and blocks its systemic silencing suppression. The NS3-GFP fusion protein and NS3 were shown to accumulate predominantly in nuclei of onion, tobacco and rice cells through transient expression assay or immunocytochemistry and electron microscopy. In addition, transgenic rice and tobacco plants expressing the NS3 did not show any apparent alteration in plant growth and morphology, although NS3 was proven to be a pathogenicity determinant in the PVX heterogenous system. Taken together, our results demonstrate that RSV NS3 is a suppressor of RNA silencing in planta, possibly through sequestering siRNA molecules generated in cells that are undergoing gene silencing.

  10. DACT2 silencing by promoter CpG methylation disrupts its regulation of epithelial-to-mesenchymal transition and cytoskeleton reorganization in breast cancer cells.

    Science.gov (United States)

    Xiang, Tingxiu; Fan, Yichao; Li, Chunhong; Li, Lili; Ying, Ying; Mu, Junhao; Peng, Weiyan; Feng, Yixiao; Oberst, Michael; Kelly, Kathleen; Ren, Guosheng; Tao, Qian

    2016-10-25

    Wnt signaling plays an important role in breast carcinogenesis. DAPPER2 (DACT2) functions as an inhibitor of canonical Wnt signaling and plays distinct roles in different cell contexts, with its role in breast tumorigenesis unclear. We investigated DACT2 expression in breast cancer cell lines and primary tumors, as well as its functions and molecular mechanisms. Results showed that DACT2 expression was silenced in 9/9 of cell lines. Promoter CpG methylation of DACT2 was detected in 89% (8/9) of cell lines, as well as in 73% (107/147) of primary tumors, but only in 20% (1/5) of surgical margin tissues and in none of normal breast tissues. Demethylation of BT549 and T47D cell lines with 5-aza-2'-deoxycytidine restored DACT2 expression along with promoter demethylation, suggesting that its downregulation in breast cancer is dependent on promoter methylation. Furthermore, ectopic expression of DACT2 induced breast cell apoptosis in vitro, and further inhibited breast tumor cell proliferation, migration and EMT, through antagonizing Wnt/β-catenin and Akt/GSK-3 signaling. Thus, these results demonstrate that DACT2 functions as a tumor suppressor for breast cancer but was frequently disrupted epigenetically in this cancer.

  11. Effect of endothelin antagonism on apnea frequency following chronic intermittent hypoxia.

    Science.gov (United States)

    Donovan, Lucas M; Liu, Yuzhen; Weiss, J Woodrow

    2014-04-01

    Chronic hypoxia increases the hypoxic ventilatory response (HVR). Augmented HVR contributes to central apneas seen in heart failure and complex sleep apnea. Endothelin receptor (ETR) antagonism decreases carotid body afferent activity following chronic intermittent hypoxia (CIH). We speculated ETR antagonism would reduce HVR and apneas following CIH. HVR and apneas were measured after exposure to CIH and room air sham (SHAM). ETR blocker Ambrisentan was administered via the chow of CIH-exposed animals from days 1 to 12 of CIH (CIH/AMB). A separate crossover group was exposed to CIH and fed normal chow (placebo) days 1-6, and Ambrisentan days 7-12 (CIH/PLA-AMB). SHAM and CIH/PLA animals were fed placebo days 1-12. The CIH/AMB and CIH/PLA-AMB rats had reduced HVR compared to CIH/PLA, similar HVR compared to sham exposed animals, and reduced apnea frequency compared to CIH/PLA animals. The reduced HVR and post-hypoxic apneas resulting from Ambrisentan administration suggests ETR antagonists may have utility in reducing central apneas following CIH. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Dynamical transitions in a pollination-herbivory interaction: a conflict between mutualism and antagonism.

    Directory of Open Access Journals (Sweden)

    Tomás A Revilla

    Full Text Available Plant-pollinator associations are often seen as purely mutualistic, while in reality they can be more complex. Indeed they may also display a diverse array of antagonistic interactions, such as competition and victim-exploiter interactions. In some cases mutualistic and antagonistic interactions are carried-out by the same species but at different life-stages. As a consequence, population structure affects the balance of inter-specific associations, a topic that is receiving increased attention. In this paper, we developed a model that captures the basic features of the interaction between a flowering plant and an insect with a larval stage that feeds on the plant's vegetative tissues (e.g. leaves and an adult pollinator stage. Our model is able to display a rich set of dynamics, the most remarkable of which involves victim-exploiter oscillations that allow plants to attain abundances above their carrying capacities and the periodic alternation between states dominated by mutualism or antagonism. Our study indicates that changes in the insect's life cycle can modify the balance between mutualism and antagonism, causing important qualitative changes in the interaction dynamics. These changes in the life cycle could be caused by a variety of external drivers, such as temperature, plant nutrients, pesticides and changes in the diet of adult pollinators.

  13. Specialization in the yucca-yucca moth obligate pollination mutualism: A role for antagonism?

    Science.gov (United States)

    Althoff, David M

    2016-10-01

    Specialized brood pollination systems involve both mutualism and antagonism in the overall interaction and have led to diversification in both plants and insects. Although largely known for mutualism, the role of the antagonistic side of the interaction in these systems has been overlooked. Specialization may be driven by plant defenses to feeding by the insect larvae that consume and kill developing plant ovules. The interaction among yuccas and yucca moths is cited as a classic example of the importance of mutualism in specialization and diversification. Pollinators moths are very host specific, but whether this specificity is due to adult pollination ability or larval feeding ability is unclear. Here, I test the potential role of antagonism in driving specialization among yuccas and yucca moths. I examined the ability of the most-polyphagous yucca moth pollinator, Tegeticula yuccasella, to pollinate and develop on five Yucca species used across its range. Yucca species endemic to the Great Plains and Texas were transplanted to a common garden in Syracuse, New York and exposed to the local pollinator moth population over 3 years. Local moths visited all but one of the Yucca species, but had drastically lower rates of successful larval development on non-natal Yucca species in comparison to the local host species. Specialization in many brood pollination systems may be strongly influenced by the antagonistic rather than the mutualistic side of the overall interaction, suggesting that antagonistic coevolution is a possible source of diversification. © 2016 Botanical Society of America.

  14. FXR antagonism of NSAIDs contributes to drug-induced liver injury identified by systems pharmacology approach

    Science.gov (United States)

    Lu, Weiqiang; Cheng, Feixiong; Jiang, Jing; Zhang, Chen; Deng, Xiaokang; Xu, Zhongyu; Zou, Shien; Shen, Xu; Tang, Yun; Huang, Jin

    2015-01-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) are worldwide used drugs for analgesic, antipyretic, and anti-inflammatory therapeutics. However, NSAIDs often cause several serious liver injuries, such as drug-induced liver injury (DILI), and the molecular mechanisms of DILI have not been clearly elucidated. In this study, we developed a systems pharmacology approach to explore the mechanism-of-action of NSAIDs. We found that the Farnesoid X Receptor (FXR) antagonism of NSAIDs is a potential molecular mechanism of DILI through systematic network analysis and in vitro assays. Specially, the quantitative real-time PCR assay reveals that indomethacin and ibuprofen regulate FXR downstream target gene expression in HepG2 cells. Furthermore, the western blot shows that FXR antagonism by indomethacin induces the phosphorylation of STAT3 (signal transducer and activator of transcription 3), promotes the activation of caspase9, and finally causes DILI. In summary, our systems pharmacology approach provided novel insights into molecular mechanisms of DILI for NSAIDs, which may propel the ways toward the design of novel anti-inflammatory pharmacotherapeutics. PMID:25631039

  15. FXR antagonism of NSAIDs contributes to drug-induced liver injury identified by systems pharmacology approach.

    Science.gov (United States)

    Lu, Weiqiang; Cheng, Feixiong; Jiang, Jing; Zhang, Chen; Deng, Xiaokang; Xu, Zhongyu; Zou, Shien; Shen, Xu; Tang, Yun; Huang, Jin

    2015-01-29

    Non-steroidal anti-inflammatory drugs (NSAIDs) are worldwide used drugs for analgesic, antipyretic, and anti-inflammatory therapeutics. However, NSAIDs often cause several serious liver injuries, such as drug-induced liver injury (DILI), and the molecular mechanisms of DILI have not been clearly elucidated. In this study, we developed a systems pharmacology approach to explore the mechanism-of-action of NSAIDs. We found that the Farnesoid X Receptor (FXR) antagonism of NSAIDs is a potential molecular mechanism of DILI through systematic network analysis and in vitro assays. Specially, the quantitative real-time PCR assay reveals that indomethacin and ibuprofen regulate FXR downstream target gene expression in HepG2 cells. Furthermore, the western blot shows that FXR antagonism by indomethacin induces the phosphorylation of STAT3 (signal transducer and activator of transcription 3), promotes the activation of caspase9, and finally causes DILI. In summary, our systems pharmacology approach provided novel insights into molecular mechanisms of DILI for NSAIDs, which may propel the ways toward the design of novel anti-inflammatory pharmacotherapeutics.

  16. Small molecule stabilization of the KSR inactive state antagonizes oncogenic Ras signalling.

    Science.gov (United States)

    Dhawan, Neil S; Scopton, Alex P; Dar, Arvin C

    2016-09-01

    Deregulation of the Ras-mitogen activated protein kinase (MAPK) pathway is an early event in many different cancers and a key driver of resistance to targeted therapies. Sustained signalling through this pathway is caused most often by mutations in K-Ras, which biochemically favours the stabilization of active RAF signalling complexes. Kinase suppressor of Ras (KSR) is a MAPK scaffold that is subject to allosteric regulation through dimerization with RAF. Direct targeting of KSR could have important therapeutic implications for cancer; however, testing this hypothesis has been difficult owing to a lack of small-molecule antagonists of KSR function. Guided by KSR mutations that selectively suppress oncogenic, but not wild-type, Ras signalling, we developed a class of compounds that stabilize a previously unrecognized inactive state of KSR. These compounds, exemplified by APS-2-79, modulate KSR-dependent MAPK signalling by antagonizing RAF heterodimerization as well as the conformational changes required for phosphorylation and activation of KSR-bound MEK (mitogen-activated protein kinase kinase). Furthermore, APS-2-79 increased the potency of several MEK inhibitors specifically within Ras-mutant cell lines by antagonizing release of negative feedback signalling, demonstrating the potential of targeting KSR to improve the efficacy of current MAPK inhibitors. These results reveal conformational switching in KSR as a druggable regulator of oncogenic Ras, and further suggest co-targeting of enzymatic and scaffolding activities within Ras-MAPK signalling complexes as a therapeutic strategy for overcoming Ras-driven cancers.

  17. FCJ-156 Hacking the Social: Internet Memes, Identity Antagonism, and the Logic of Lulz.

    Directory of Open Access Journals (Sweden)

    Ryan M. Milner

    2013-12-01

    Full Text Available 4chan and reddit are participatory media collectives undergirded by a “logic of lulz” that favours distanced irony and critique. It often works at the expense of core identity categories like race and gender. However, the logic need not be entirely counterproductive to public discourse. Provided that diverse identities find voice instead of exclusion, these sites may facilitate vibrant, agonistic discussion instead of disenfranchising antagonism. In order to assess this potential for productive agonism, I undertook a critical discourse analysis of these collectives. Emphasising the image memes they produce, I evaluated discourses on race and gender. Both race and gender representations were dominated by familiar stereotypes and partial representations. However, while dissenting perspectives on race were repressed or excluded, dissenting perspectives on gender were vocalised and contested. The ‘logic of lulz’ facilitated both dominance and counter, each articulated with heavy reliance on irony and critique. This logic ambiguously balanced agonism and antagonism, but contestation provided sharper engagement than repression.

  18. Seeds of the Wild Progenitor of Maize Possess Bacteria That Antagonize Foodborne Pathogens.

    Science.gov (United States)

    Shehata, Hanan R; Griffiths, Mansel W; Raizada, Manish N

    2017-04-01

    Endophytes are microorganisms that inhabit plant tissues without causing disease. Some endophytes help their hosts to combat pathogens. Here we explored the hypothesis that the plant-derived foods consumed by humans and other animals host endophytes that also antagonize foodborne pathogens or food-rotting agents. Our laboratory previously cultured a library of bacterial endophytes from different members of the maize/corn family (Zea) including wild relatives. Here, 190 of these endophytes were screened for their ability to antagonize four foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Clostridium perfringens, and Salmonella enterica Newport) and a food spoiling agent (Pseudomonas fluorescens) using dual culture assays. Two Paenibacillus polymyxa endophytes (strains 3C6 and 3G11) were found to inhibit the growth of all five deleterious strains on agar. Using conserved polymerase chain reaction primers and sequencing, both beneficial endophytes were found to encode polymyxin genes, suggesting a potential antibacterial mechanism of action. Polymyxin production by both strains was confirmed using enzyme-linked immunosorbent assay. Strains 3C6 and 3G11 originated, respectively, from the seeds of the wild Central American maize species Zea diploperennis, and the wild ancestor of modern maize, Zea mays ssp parviglumis (Parviglumis). As the latter is the direct ancestor of modern maize, we discuss the role its endophyte(s) may have played in promoting crop domestication by suppressing foodborne pathogens and/or food-spoilage agents.

  19. Antagonism of cyanide toxicity by isosorbide dinitrate: possible role of nitric oxide.

    Science.gov (United States)

    Sun, P; Borowitz, J L; Kanthasamy, A G; Kane, M D; Gunasekar, P G; Isom, G E

    1995-12-15

    In a search for improved cyanide antidotes, the efficacy of isosorbide dinitrate (ISDN), was compared with that of the known cyanide antidote, NaNO2. ISDN was as effective as an optimal dose of NaNO2 in protecting mice against cyanide lethality. To study the mechanism involved, the extent of formation of the cyanide scavenger, methemoglobin, in the action of ISDN was determined. ISDN (300 mg/kg, p.o.) increased methemoglobin from 5 to 10% of total hemoglobin, while, in contrast, NaNO2 (100 mg/kg, i.p.) increased methemoglobin levels to 50% of total hemoglobin. Lowering the dose of NaNO2 to 30 mg/kg reduced methemoglobin levels to approximately 10% of total hemoglobin and in turn nearly abolished its antidotal effect. Decreasing methemoglobin to less than control levels using methylene blue failed to abolish cyanide antagonism by ISDN. Thus, methemoglobin formation by ISDN does not account for its antidotal action. Further studies comparing the respiratory depressant effects of cyanide in the presence of ISDN or NaNO2 also indicated that these two antidotes have different mechanisms of action. Efforts to produce tolerance to the antidotal effect of ISDN against cyanide toxicity were unsuccessful. It is suggested that the well-known ability of ISDN to generate nitric oxide may account for the noted cyanide antagonism.

  20. IFITM Proteins Restrict HIV-1 Infection by Antagonizing the Envelope Glycoprotein

    Directory of Open Access Journals (Sweden)

    Jingyou Yu

    2015-10-01

    Full Text Available The interferon-induced transmembrane (IFITM proteins have been recently shown to restrict HIV-1 and other viruses. Here, we provide evidence that IFITM proteins, particularly IFITM2 and IFITM3, specifically antagonize the HIV-1 envelope glycoprotein (Env, thereby inhibiting viral infection. IFITM proteins interact with HIV-1 Env in viral producer cells, leading to impaired Env processing and virion incorporation. Notably, the level of IFITM incorporation into HIV-1 virions does not strictly correlate with the extent of inhibition. Prolonged passage of HIV-1 in IFITM-expressing T lymphocytes leads to emergence of Env mutants that overcome IFITM restriction. The ability of IFITMs to inhibit cell-to-cell infection can be extended to HIV-1 primary isolates, HIV-2 and SIVs; however, the extent of inhibition appears to be virus-strain dependent. Overall, our study uncovers a mechanism by which IFITM proteins specifically antagonize HIV-1 Env to restrict HIV-1 infection and provides insight into the specialized role of IFITMs in HIV infection.

  1. Structural basis for dsRNA recognition and interferon antagonism by Ebola VP35

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Daisy W.; Prins, Kathleen C.; Borek, Dominika M.; Farahbakhsh, Mina; Tufariello, JoAnn M.; Ramanan, Parameshwaran; Nix, Jay C.; Helgeson, Luke A.; Otwinowski, Zbyszek; Honzatko, Richard B.; Basler, Christopher F.; Amarasinghe, Gaya K. (Sinai); (Iowa State); (LBNL); (UTSMC)

    2010-03-12

    Ebola viral protein 35 (VP35), encoded by the highly pathogenic Ebola virus, facilitates host immune evasion by antagonizing antiviral signaling pathways, including those initiated by RIG-I-like receptors. Here we report the crystal structure of the Ebola VP35 interferon inhibitory domain (IID) bound to short double-stranded RNA (dsRNA), which together with in vivo results reveals how VP35-dsRNA interactions contribute to immune evasion. Conserved basic residues in VP35 IID recognize the dsRNA backbone, whereas the dsRNA blunt ends are 'end-capped' by a pocket of hydrophobic residues that mimic RIG-I-like receptor recognition of blunt-end dsRNA. Residues critical for RNA binding are also important for interferon inhibition in vivo but not for viral polymerase cofactor function of VP35. These results suggest that simultaneous recognition of dsRNA backbone and blunt ends provides a mechanism by which Ebola VP35 antagonizes host dsRNA sensors and immune responses.

  2. Aggression, Sibling Antagonism, and Theory-of-Mind During the First Year of Siblinghood: A Developmental Cascade Model

    Science.gov (United States)

    Song, Ju-Hyun; Volling, Brenda L.; Lane, Jonathan D.; Wellman, Henry M.

    2016-01-01

    A developmental cascade model was tested to examine longitudinal associations among firstborn children’s aggression, Theory-of-Mind, and antagonism toward their younger sibling during the first year of siblinghood. Aggression and Theory-of-Mind were assessed before the birth of a sibling, and 4 and 12 months after the birth, and antagonism was examined at 4 and 12 months in a sample of 208 firstborn children (initial M age = 30 months, 56% girls) from primarily European American, middle- class families. Firstborns’ aggression consistently predicted high sibling antagonism both directly and through poorer Theory-of-Mind. Results highlight the importance of examining longitudinal influences across behavioral, social-cognitive, and relational factors that are closely intertwined even from the early years of life. PMID:27096923

  3. Symbiont interactions in a tripartite mutualism: exploring the presence and impact of antagonism between two fungus-growing ant mutualists.

    Directory of Open Access Journals (Sweden)

    Michael Poulsen

    Full Text Available Mutualistic associations are shaped by the interplay of cooperation and conflict among the partners involved, and it is becoming increasingly clear that within many mutualisms multiple partners simultaneously engage in beneficial interactions. Consequently, a more complete understanding of the dynamics within multipartite mutualism communities is essential for understanding the origin, specificity, and stability of mutualisms. Fungus-growing ants cultivate fungi for food and maintain antibiotic-producing Pseudonocardia actinobacteria on their cuticle that help defend the cultivar fungus from specialized parasites. Within both ant-fungus and ant-bacterium mutualisms, mixing of genetically distinct strains can lead to antagonistic interactions (i.e., competitive conflict, which may prevent the ants from rearing multiple strains of either of the mutualistic symbionts within individual colonies. The success of different ant-cultivar-bacterium combinations could ultimately be governed by antagonistic interactions between the two mutualists, either as inhibition of the cultivar by Pseudonocardia or vice versa. Here we explore cultivar-Pseudonocardia antagonism by evaluating in vitro interactions between strains of the two mutualists, and find frequent antagonistic interactions both from cultivars towards Pseudonocardia and vice versa. To test whether such in vitro antagonistic interactions affect ant colonies in vivo, we performed sub-colony experiments using species of Acromyrmex leaf-cutting ants. We created novel ant-fungus-bacterium pairings in which there was antagonism from one, both, or neither of the ants' microbial mutualists, and evaluated the effect of directional antagonism on cultivar biomass and Pseudonocardia abundance on the cuticle of workers within sub-colonies. Despite the presence of frequent in vitro growth suppression between cultivars and Pseudonocardia, antagonism from Pseudonocardia towards the cultivar did not reduce sub

  4. Transcription-dependent silencing of inducible convergent transgenes in transgenic mice

    Directory of Open Access Journals (Sweden)

    Calero-Nieto Fernando J

    2010-01-01

    Full Text Available Abstract Background Silencing of transgenes in mice is a common phenomenon typically associated with short multi-copy transgenes. We have investigated the regulation of the highly inducible human granulocyte-macrophage colony-stimulating-factor gene (Csf2 in transgenic mice. Results In the absence of any previous history of transcriptional activation, this transgene was expressed in T lineage cells at the correct inducible level in all lines of mice tested. In contrast, the transgene was silenced in a specific subset of lines in T cells that had encountered a previous episode of activation. Transgene silencing appeared to be both transcription-dependent and mediated by epigenetic mechanisms. Silencing was accompanied by loss of DNase I hypersensitive sites and inability to recruit RNA polymerase II upon stimulation. This pattern of silencing was reflected by increased methylation and decreased acetylation of histone H3 K9 in the transgene. We found that silenced lines were specifically associated with a single pair of tail-to-tail inverted repeated copies of the transgene embedded within a multi-copy array. Conclusions Our study suggests that epigenetic transgene silencing can result from convergent transcription of inverted repeats which can lead to silencing of an entire multi-copy transgene array. This mechanism may account for a significant proportion of the reported cases of transgene inactivation in mice.

  5. Virus-induced gene silencing and Agrobacterium tumefaciens-mediated transient expression in Nicotiana tabacum

    NARCIS (Netherlands)

    Zhang, Z.; Thomma, B.P.H.J.

    2014-01-01

    Virus-induced gene silencing (VIGS) is a rapid method for transient silencing of plant genes. In this chapter, we describe the methodology for Tobacco rattle virus (TRV)-based VIGS in Nicotiana tabacum. In combination with subsequent co-expression of the tomato immune receptor Ve1 and the

  6. Protocol: using virus-induced gene silencing to study the arbuscular mycorrhizal symbiosis in Pisum sativum

    DEFF Research Database (Denmark)

    Grønlund, Mette; Olsen, Anne; Johansen, Elisabeth

    2010-01-01

    Virus-induced gene silencing (VIGS) is an alternative reverse genetics tool for silencing of genes in some plants, which are difficult to transform. The pea early-browning virus (PEBV) has been developed as a VIGS vector and used in pea for functional analysis of several genes. However, the avail...

  7. Self-Silencing, Emotional Awareness, and Eating Behaviors in College Women

    Science.gov (United States)

    Shouse, Sarah H.; Nilsson, Johanna

    2011-01-01

    Self-silencing (or the suppression of expressing one's thoughts, feelings, and needs) can have a negative impact on the mental health of women, from depression to disordered eating behaviors. The authors examined the relationship between self-silencing and disordered eating as well as intuitive eating. The authors also explored whether emotional…

  8. Identification and characterization of two RNA silencing suppressors encoded by ophioviruses

    NARCIS (Netherlands)

    Robles Luna, Gabriel; Reyes, Carina A.; Peña, Eduardo J.; Ocolotobiche, Eliana; Baeza, Cecilia; Borniego, Maria Belén; Kormelink, Richard; García, María Laura

    2017-01-01

    Citrus psorosis virus and Mirafiori lettuce big-vein virus are two members of the genus Ophiovirus, family Ophioviridae. So far, how these viruses can interfere in the antiviral RNA silencing pathway is not known. In this study, using a local GFP silencing assay on Nicotiana benthamiana, the

  9. Distinct Effects of p19 RNA Silencing Suppressor on Small RNA Mediated Pathways in Plants.

    Directory of Open Access Journals (Sweden)

    Levente Kontra

    2016-10-01

    Full Text Available RNA silencing is one of the main defense mechanisms employed by plants to fight viruses. In change, viruses have evolved silencing suppressor proteins to neutralize antiviral silencing. Since the endogenous and antiviral functions of RNA silencing pathway rely on common components, it was suggested that viral suppressors interfere with endogenous silencing pathway contributing to viral symptom development. In this work, we aimed to understand the effects of the tombusviral p19 suppressor on endogenous and antiviral silencing during genuine virus infection. We showed that ectopically expressed p19 sequesters endogenous small RNAs (sRNAs in the absence, but not in the presence of virus infection. Our presented data question the generalized model in which the sequestration of endogenous sRNAs by the viral suppressor contributes to the viral symptom development. We further showed that p19 preferentially binds the perfectly paired ds-viral small interfering RNAs (vsiRNAs but does not select based on their sequence or the type of the 5' nucleotide. Finally, co-immunoprecipitation of sRNAs with AGO1 or AGO2 from virus-infected plants revealed that p19 specifically impairs vsiRNA loading into AGO1 but not AGO2. Our findings, coupled with the fact that p19-expressing wild type Cymbidium ringspot virus (CymRSV overcomes the Nicotiana benthamiana silencing based defense killing the host, suggest that AGO1 is the main effector of antiviral silencing in this host-virus combination.

  10. Horreur et silence : le personnage de Pierre Cange dans l’œuvre narrative de Vercors

    Directory of Open Access Journals (Sweden)

    Elisabetta Sibilio

    2015-11-01

    Full Text Available Vercors, who achieved fame thanks to his first novel, Le silence de la mer, published undercover in 1942, makes silence one of the main themes in his work. Silence, which is the paradoxical expression of what Vercors calls “la qualité d’homme”, appears in his work according to two major categories: on the one hand the proud and resilient silence of the protagonist of Silence de la mer or of Arnaud, the main character of the short story Le démenti, who loses his life for having maintained an obstinate silence in the hands of his torturers; on the other hand, the guilty and desperate shameful silence of those who had lost their own humanity when faced with the horror of the camps or had hoped to save their lives by col-laborating with the enemy. This paper will examine three of Vercors’ texts, Les armes de la nuit (1946, La puissance du jour (1951 and Le tigre d’Anvers (1986, which have Pierre Cange as protagonist, a member of the Resistance, deported, who through his own experience is faced with the funda-mental theme of silence.

  11. Performing Silence: Gender, Violence, and Resistance in Women's Narratives from Lahaul, India

    Science.gov (United States)

    Bhattacharya, Himika

    2009-01-01

    This article presents two different ways of understanding silence, through a discussion of women's narratives of violence from Lahaul, India. Here I illustrate how feminist ethnography works its way into re-conceptualizing silence as a tool women use to resist existing patriarchal discourses of honor, tribe and nation. (Contains 1 note.)

  12. Giving Voice: Narrating silence, history and memory in André Brink ...

    African Journals Online (AJOL)

    This essay examines André Brink's two most recent novels, The Other Side of Silence (2002) and Before I Forget (2004), in terms of their voicing of silence and the rewriting of history and memory. Each has a theme familiar to Brink's readers – an historical story of colonial violence and violation avenged; and the recounting ...

  13. Analysing the significance of silence in qualitative interviewing: questioning and shifting power relations

    DEFF Research Database (Denmark)

    Bengtsson, Tea Torbenfeldt; Fynbo, Lars

    2017-01-01

    In this article we analyse the significance of silence in qualitative interviews with 36 individuals interviewed about high-risk, illegal activities. We describe how silence expresses a dynamic power relationship between interviewer and interviewee. In the analysis, we focus on two different type...

  14. Down-Regulation of Gene Expression by RNA-Induced Gene Silencing

    Science.gov (United States)

    Travella, Silvia; Keller, Beat

    Down-regulation of endogenous genes via post-transcriptional gene silencing (PTGS) is a key to the characterization of gene function in plants. Many RNA-based silencing mechanisms such as post-transcriptional gene silencing, co-suppression, quelling, and RNA interference (RNAi) have been discovered among species of different kingdoms (plants, fungi, and animals). One of the most interesting discoveries was RNAi, a sequence-specific gene-silencing mechanism initiated by the introduction of double-stranded RNA (dsRNA), homologous in sequence to the silenced gene, which triggers degradation of mRNA. Infection of plants with modified viruses can also induce RNA silencing and is referred to as virus-induced gene silencing (VIGS). In contrast to insertional mutagenesis, these emerging new reverse genetic approaches represent a powerful tool for exploring gene function and for manipulating gene expression experimentally in cereal species such as barley and wheat. We examined how RNAi and VIGS have been used to assess gene function in barley and wheat, including molecular mechanisms involved in the process and available methodological elements, such as vectors, inoculation procedures, and analysis of silenced phenotypes.

  15. Interleukin-1 antagonism moderates the inflammatory state associated with Type 1 diabetes during clinical trials conducted at disease onset

    DEFF Research Database (Denmark)

    Cabrera, Susanne M; Wang, Xujing; Chen, Yi-Guang

    2016-01-01

    It was hypothesized that IL-1 antagonism would preserve β-cell function in new onset Type 1 diabetes (T1D). However, the Anti-Interleukin-1 in Diabetes Action (AIDA) and TrialNet Canakinumab (TN-14) trials failed to show efficacy of IL-1 receptor antagonist (IL-1Ra) or canakinumab, as measured...... to their treatment arm. While the transcriptional signatures from the two trials were distinct, both therapies achieved varying immunomodulation consistent with IL-1 inhibition. On average, IL-1 antagonism resulted in modest normalization relative to healthy controls. At endpoint, signatures were quantified using...

  16. SAMD9 is an innate antiviral host factor with stress response properties that can be antagonized by poxviruses.

    Science.gov (United States)

    Liu, Jia; McFadden, Grant

    2015-02-01

    We show that SAMD9 is an innate host antiviral stress response element that participates in the formation of antiviral granules. Poxviruses, myxoma virus and vaccinia virus specifically, utilize a virus-encoded host range factor(s), such as a member of the C7L superfamily, to antagonize SAMD9 to prevent granule formation in a eukaryotic initiation factor 2α (eIF2α)-independent manner. When SAMD9 is stimulated due to failure of the viral antagonism during infection, the resulting antiviral granules exhibit properties different from those of the canonical stress granules. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. Postpartum Depression: How Childbirth Educators Can Help Break the Silence

    Science.gov (United States)

    Zauderer, Cheryl

    2009-01-01

    The voices of women suffering from postpartum depression are often silent. Women are reluctant to reveal to others that they are unhappy after the birth of their babies. Much has been written on possible causes, risk factors, and treatments for postpartum depression, but little has been done to investigate why women take so long to seek help. Early detection and treatment are key to a full recovery. Childbirth educators are in the position to offer anticipatory guidance on possible complications of the postpartum period, including postpartum depression. This article explores why women with postpartum depression choose to suffer in silence and suggests how childbirth educators can help new mothers find their voices. PMID:20190853

  18. A Resonant Silence: For an Ethnographic History of Abortion

    Directory of Open Access Journals (Sweden)

    Flávia de Mattos Motta

    2008-05-01

    Full Text Available By using methods of the fields of History and Anthropology, this study investigated the practice of abortion in southern Brazil in the first half of the twentieth century. The examination of primary sources and interviews with elderly women intended to unveil a huge silence around this practice, which leaves very few historical sources to be investigated, and hides those memories. This text presents data collected by this survey and analyzes the diversity of representations over abortion and the ambiguities that this theme causes on the subjects involved. The practice of abortion must be understood as inserted into a context of power. The subjects operate from multiple sources of knowledge and within a morality network composed of contradictory elements.

  19. Hearing the Silence: Children’s Voices on Violence

    Directory of Open Access Journals (Sweden)

    Kathryn S. Collins

    2003-05-01

    Full Text Available Each year more than five million children in the United States are exposed to traumatizing events in their communities. This paper presents a discussion of multiple areas in violence and victimization research that needs to be continued as well as provides suggestions on how to un-silence child survivors through bridging the gaps between research and practice. It reviews the overarching problem of violence in the U.S. at the domestic and global levels and the effects of victimization. Suggestions on how to study possible mediators and moderators of victimization and individual and family adjustment, including: 1 The ecological perspective; 2 Court process and verdict; and 3Utilization of victim services, are explored. Finally, a rationale and examples of combining qualitative and quantitative methods in future research that uses children’s attributions of violence as a mediator are presented.

  20. Sonic memory interventions against politics of urban silencing

    Directory of Open Access Journals (Sweden)

    Hofman Ana

    2017-01-01

    Full Text Available We discuss the political implications of the noise/silence dialectic in order to reflect on the urban and social materialities of sonic memory activism in the post- Yugoslav space. We see the privatization of public space as one of the defining issues of current socio-political tensions and we strive to offer a more nuanced model for thinking about grassroots practices of musicking and listening in the context of resistance and power and control redistribution. Discussing sonic interventions in Ljubljana and Belgrade enables us both to uncover how important global processes are reflected in these local contexts and to locate diversity of present practices of resistance. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 177004: Serbian Musical Identities Within Local and Global Frameworks: Traditions, Changes, Challenges

  1. SOCS3 Silencing Attenuates Eosinophil Functions in Asthma Patients

    Science.gov (United States)

    Zafra, Mª Paz; Cañas, Jose A.; Mazzeo, Carla; Gámez, Cristina; Sanz, Veronica; Fernández-Nieto, Mar; Quirce, Santiago; Barranco, Pilar; Ruiz-Hornillos, Javier; Sastre, Joaquín; del Pozo, Victoria

    2015-01-01

    Eosinophils are one of the key inflammatory cells in asthma. Eosinophils can exert a wide variety of actions through expression and secretion of multiple molecules. Previously, we have demonstrated that eosinophils purified from peripheral blood from asthma patients express high levels of suppressor of cytokine signaling 3 (SOCS3). In this article, SOCS3 gene silencing in eosinophils from asthmatics has been carried out to achieve a better understanding of the suppressor function in eosinophils. SOCS3 siRNA treatment drastically reduced SOCS3 expression in eosinophils, leading to an inhibition of the regulatory transcription factors GATA-3 and FoxP3, also interleukin (IL)-10; in turn, an increased STAT3 phosphorilation was observed. Moreover, SOCS3 abrogation in eosinophils produced impaired migration, adhesion and degranulation. Therefore, SOCS3 might be regarded as an important regulator implicated in eosinophil mobilization from the bone marrow to the lungs during the asthmatic process. PMID:25764157

  2. Prognostic significance of aberrantly silenced ANPEP expression in prostate cancer

    DEFF Research Database (Denmark)

    Sørensen, Karina Dalsgaard; Abildgaard, Mette Opstrup; Haldrup, Christa

    2013-01-01

    Background:Novel biomarkers for prostate cancer (PC) are urgently needed. This study investigates the expression, epigenetic regulation, and prognostic potential of ANPEP in PC.Methods:Aminopeptidase N (APN; encoded by ANPEP) expression was analysed by immunohistochemistry using tissue microarrays...... in three hypermethylated prostate cell lines, suggesting epigenetic silencing. Negative APN immunoreactivity was significantly associated with short RFS and short CSS in the RP and CT cohort, respectively, independently of routine clinicopathological predictors. Combining APN with a known angiogenesis...... marker (vascular endothelial growth factor or microvessel density) improved risk prediction significantly in both cohorts.Conclusion:Our results suggest negative APN immunoreactivity as a new independent adverse prognostic factor for patients with clinically localised PC and, furthermore, that epigenetic...

  3. Silencing of voices in a Swedish science classroom

    Science.gov (United States)

    Ramos de Robles, S. Lizette

    2018-03-01

    From a sociocultural perspective, I discuss data from a Swedish science classroom presented in María Gómez's article "Student Explanations of their Science Teachers' Assessments, Grading Practices, and How they learn Science". In this discussion, I focus on the need to change existing conceptions of assessment in the teaching and learning of science. Next, I talk about the importance of taking into consideration the dialectic between agency and passivity as filters in order to understand what student silence may signify in science classes as well as in relation to their perceptions of assessment. I conclude with the importance of the teacher's role in developing formative assessment, along with the challenges in developing assessments which transform science education into a relevant field of knowledge for both students and society at large.

  4. Flexible tools for gene expression and silencing in tomato.

    Science.gov (United States)

    Fernandez, Ana I; Viron, Nicolas; Alhagdow, Moftah; Karimi, Mansour; Jones, Matthew; Amsellem, Ziva; Sicard, Adrien; Czerednik, Anna; Angenent, Gerco; Grierson, Donald; May, Sean; Seymour, Graham; Eshed, Yuval; Lemaire-Chamley, Martine; Rothan, Christophe; Hilson, Pierre

    2009-12-01

    As a genetic platform, tomato (Solanum lycopersicum) benefits from rich germplasm collections and ease of cultivation and transformation that enable the analysis of biological processes impossible to investigate in other model species. To facilitate the assembly of an open genetic toolbox designed to study Solanaceae, we initiated a joint collection of publicly available gene manipulation tools. We focused on the characterization of promoters expressed at defined time windows during fruit development, for the regulated expression or silencing of genes of interest. Five promoter sequences were captured as entry clones compatible with the versatile MultiSite Gateway format: PPC2, PG, TPRP, and IMA from tomato and CRC from Arabidopsis (Arabidopsis thaliana). Corresponding transcriptional fusions were made with the GUS gene, a nuclear-localized GUS-GFP reporter, and the chimeric LhG4 transcription factor. The activity of the promoters during fruit development and in fruit tissues was confirmed in transgenic tomato lines. Novel Gateway destination vectors were generated for the transcription of artificial microRNA (amiRNA) precursors and hairpin RNAs under the control of these promoters, with schemes only involving Gateway BP and LR Clonase reactions. Efficient silencing of the endogenous phytoene desaturase gene was demonstrated in transgenic tomato lines producing a matching amiRNA under the cauliflower mosaic virus 35S or PPC2 promoter. Lastly, taking advantage of the pOP/LhG4 two-component system, we found that well-characterized flower-specific Arabidopsis promoters drive the expression of reporters in patterns generally compatible with heterologous expression. Tomato lines and plasmids will be distributed through a new Nottingham Arabidopsis Stock Centre service unit dedicated to Solanaceae resources.

  5. Polyphenoloxidase Silencing Affects Latex Coagulation in Taraxacum Species1[W

    Science.gov (United States)

    Wahler, Daniela; Gronover, Christian Schulze; Richter, Carolin; Foucu, Florence; Twyman, Richard M.; Moerschbacher, Bruno M.; Fischer, Rainer; Muth, Jost; Prüfer, Dirk

    2009-01-01

    Latex is the milky sap that is found in many different plants. It is produced by specialized cells known as laticifers and can comprise a mixture of proteins, carbohydrates, oils, secondary metabolites, and rubber that may help to prevent herbivory and protect wound sites against infection. The wound-induced browning of latex suggests that it contains one or more phenol-oxidizing enzymes. Here, we present a comprehensive analysis of the major latex proteins from two dandelion species, Taraxacum officinale and Taraxacum kok-saghyz, and enzymatic studies showing that polyphenoloxidase (PPO) is responsible for latex browning. Electrophoretic analysis and amino-terminal sequencing of the most abundant proteins in the aqueous latex fraction revealed the presence of three PPO-related proteins generated by the proteolytic cleavage of a single precursor (pre-PPO). The laticifer-specific pre-PPO protein contains a transit peptide that can target reporter proteins into chloroplasts when constitutively expressed in dandelion protoplasts, perhaps indicating the presence of structures similar to plastids in laticifers, which lack genuine chloroplasts. Silencing the PPO gene by constitutive RNA interference in transgenic plants reduced PPO activity compared with wild-type controls, allowing T. kok-saghyz RNA interference lines to expel four to five times more latex than controls. Latex fluidity analysis in silenced plants showed a strong correlation between residual PPO activity and the coagulation rate, indicating that laticifer-specific PPO plays a major role in latex coagulation and wound sealing in dandelions. In contrast, very little PPO activity is found in the latex of the rubber tree Hevea brasiliensis, suggesting functional divergence of latex proteins during plant evolution. PMID:19605551

  6. Dismantling the Silence: LGBTQ Aging Emerging From the Margins.

    Science.gov (United States)

    Fredriksen-Goldsen, Karen I

    2017-02-01

    Historical, environmental, and cultural contexts intersect with aging, sexuality, and gender across communities and generations. My scholarship investigates health and well-being over the life course across marginalized communities, including LGBTQ (lesbian, gay, bisexual, transgender, and queer) midlife and older adults, native communities experiencing cardiovascular risk, and families in China living with HIV, in order to balance the realities of unique lives in contemporary society. By probing the intersection of age, sexuality, and gender, my analysis is informed by both personal and professional experiences. With the death of my partner occurring at a time of profound invisibility and silence before HIV/AIDS, I found my life out of sync, experiencing a loss without a name. My life was thrust into a paradox: My relationship was defined by a world that refused to recognize it. This essay provides an opportunity for me to weave together how such critical turning points in my own life helped shape my approach to gerontology and how gerontology has informed my work and life. Reflecting on this journey, I illustrate the ways in which historical, structural, environmental, psychosocial, and biological factors affect equity, and the health-promoting and adverse pathways to health and well-being across marginalized communities. Although gerontology as a discipline has historically silenced the lives of marginalized older adults, it has much to learn from these communities. The growing and increasingly diverse older adult population provides us with unique opportunities to better understand both cultural variations and shared experiences in aging over the life course. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Silencing Intersectin 1 Slows Orthotopic Neuroblastoma Growth in Mice.

    Science.gov (United States)

    Harris, Jamie; Herrero-Garcia, Erika; Russo, Angela; Kajdacsy-Balla, Andre; O'Bryan, John P; Chiu, Bill

    2017-11-01

    Neuroblastoma accounts for 15% of all pediatric cancer deaths. Intersectin 1 (ITSN1), a scaffold protein involved in phosphoinositide 3-kinase (PI3K) signaling, regulates neuroblastoma cells independent of MYCN status. We hypothesize that by silencing ITSN1 in neuroblastoma cells, tumor growth will be decreased in an orthotopic mouse tumor model. SK-N-AS neuroblastoma cells transfected with empty vector (pSR), vectors expressing scrambled shRNA (pSCR), or shRNAs targeting ITSN1 (sh#1 and sh#2) were used to create orthotopic neuroblastoma tumors in mice. Volume was monitored weekly with ultrasound. End-point was tumor volume >1000 mm. Tumor cell lysates were analyzed with anti-ITSN1 antibody by Western blot. Orthotopic tumors were created in all cell lines. Twenty-five days post injection, pSR tumor size was 917.6±247.7 mm, pSCR was 1180±159.9 mm, sh#1 was 526.3±212.8 mm, and sh#2 was 589.2±74.91 mm. sh#1-tumors and sh#2-tumors were smaller than pSCR (P=0.02), no difference between sh#1 and sh#2. Survival was superior in sh#2-tumors (P=0.02), trended towards improved survival in sh#1-tumors (P=0.09), compared with pSCR-tumors, no difference in pSR tumors. Western blot showed decreased ITSN1 expression in sh#1 and sh#2 compared with pSR and pSCR. Silencing ITSN1 in neuroblastoma cells led to decreased tumor growth in an orthotopic mouse model. Orthotopic animal models can provide insight into the role of ITSN1 pathways in neuroblastoma tumorigenesis.

  8. AMFR gene silencing inhibits the differentiation of porcine preadipocytes.

    Science.gov (United States)

    Chen, C Z; Zhu, Y N; Chai, M L; Dai, L S; Gao, Y; Jiang, H; Zhang, L J; Ding, Y; Liu, S Y; Li, Q Y; Lu, W F; Zhang, J B

    2016-04-07

    Our study clarifies the role of the autocrine motility factor receptor (AMFR) gene in porcine preadipocyte differentiation. AMFR-siRNA was transfected into porcine preadipocytes and the preadipocytes were induced to differentiation. Subsequently, qRT-PCR was conducted to examine changes in mRNA expression of a series of genes in porcine preadipocytes, including AMFR, sterol-regulatory element-binding protein-1a (SREBP1a), SREBP2, insulin-induced gene 1 (Insig1), and Insig2. Expression changes in the mRNA of genes regulating adipocyte differentiation were also analyzed using qRT-PCR, including peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein alpha (C/EBPα), and Kruppel-like factor 2 (KLF2). Western blot analysis was conducted to examine the changes in AMFR protein expression in porcine preadipocytes. Additionally, morphological changes in differentiated porcine preadipocytes were examined by oil red O staining, and changes in optical density (OD) values were measured using an ultraviolet spectrophotometer. At 24 h after transfection with AMFR-siRNA, AMFR mRNA expression significantly reduced (P SREBP1a, SREBP2, Insig1, and C/EBPα was significantly reduced (P < 0.01), whereas the expression of KLF2 mRNA was significantly elevated (P < 0.01). After induction of preadipocyte differentiation, the number of lipid droplets decreased in the AMFR-silenced group, and the OD value markedly reduced (P < 0.05). In addition, the expression of C/EBPα mRNA significantly decreased (P < 0.05), whereas the expression of KLF2 mRNA considerably increased (P < 0.05). Taken together, silencing of the AMFR gene inhibits the differentiation of porcine preadipocytes.

  9. Hypoxia Silences Retrotrapezoid Nucleus Respiratory Chemoreceptors via Alkalosis

    Science.gov (United States)

    Basting, Tyler M.; Burke, Peter G.R.; Kanbar, Roy; Viar, Kenneth E.; Stornetta, Daniel S.; Stornetta, Ruth L.

    2015-01-01

    In conscious mammals, hypoxia or hypercapnia stimulates breathing while theoretically exerting opposite effects on central respiratory chemoreceptors (CRCs). We tested this theory by examining how hypoxia and hypercapnia change the activity of the retrotrapezoid nucleus (RTN), a putative CRC and chemoreflex integrator. Archaerhodopsin-(Arch)-transduced RTN neurons were reversibly silenced by light in anesthetized rats. We bilaterally transduced RTN and nearby C1 neurons with Arch (PRSx8-ArchT-EYFP-LVV) and measured the cardiorespiratory consequences of Arch activation (10 s) in conscious rats during normoxia, hypoxia, or hyperoxia. RTN photoinhibition reduced breathing equally during non-REM sleep and quiet wake. Compared with normoxia, the breathing frequency reduction (ΔfR) was larger in hyperoxia (65% FiO2), smaller in 15% FiO2, and absent in 12% FiO2. Tidal volume changes (ΔVT) followed the same trend. The effect of hypoxia on ΔfR was not arousal-dependent but was reversed by reacidifying the blood (acetazolamide; 3% FiCO2). ΔfR was highly correlated with arterial pH up to arterial pH (pHa) 7.5 with no frequency inhibition occurring above pHa 7.53. Blood pressure was minimally reduced suggesting that C1 neurons were very modestly inhibited. In conclusion, RTN neurons regulate eupneic breathing about equally during both sleep and wake. RTN neurons are the first putative CRCs demonstrably silenced by hypocapnic hypoxia in conscious mammals. RTN neurons are silent above pHa 7.5 and increasingly active below this value. During hyperoxia, RTN activation maintains breathing despite the inactivity of the carotid bodies. Finally, during hypocapnic hypoxia, carotid body stimulation increases breathing frequency via pathways that bypass RTN. PMID:25589748

  10. Dismantling the Silence: LGBTQ Aging Emerging From the Margins

    Science.gov (United States)

    Fredriksen-Goldsen, Karen I.

    2017-01-01

    Historical, environmental, and cultural contexts intersect with aging, sexuality, and gender across communities and generations. My scholarship investigates health and well-being over the life course across marginalized communities, including LGBTQ (lesbian, gay, bisexual, transgender, and queer) midlife and older adults, native communities experiencing cardiovascular risk, and families in China living with HIV, in order to balance the realities of unique lives in contemporary society. By probing the intersection of age, sexuality, and gender, my analysis is informed by both personal and professional experiences. With the death of my partner occurring at a time of profound invisibility and silence before HIV/AIDS, I found my life out of sync, experiencing a loss without a name. My life was thrust into a paradox: My relationship was defined by a world that refused to recognize it. This essay provides an opportunity for me to weave together how such critical turning points in my own life helped shape my approach to gerontology and how gerontology has informed my work and life. Reflecting on this journey, I illustrate the ways in which historical, structural, environmental, psychosocial, and biological factors affect equity, and the health-promoting and adverse pathways to health and well-being across marginalized communities. Although gerontology as a discipline has historically silenced the lives of marginalized older adults, it has much to learn from these communities. The growing and increasingly diverse older adult population provides us with unique opportunities to better understand both cultural variations and shared experiences in aging over the life course. PMID:28053011

  11. Position-Dependent Methylation and Transcriptional Silencing of Transgenes in Inverted T-DNA Repeats: Implications for Posttranscriptional Silencing of Homologous Host Genes in Plants

    Science.gov (United States)

    Stam, Maike; Viterbo, Ada; Mol, Joseph N. M.; Kooter, Jan M.

    1998-01-01

    Posttranscriptional silencing of chalcone synthase (Chs) genes in petunia transformants occurs by introducing T-DNAs that contain a promoter-driven or promoterless Chs transgene. With the constructs we used, silencing occurs only by T-DNA loci which are composed of two or more T-DNA copies that are arranged as inverted repeats (IRs). Since we are interested in the mechanism by which these IR loci induce silencing, we have analyzed different IR loci and nonsilencing single-copy (S) T-DNA loci with respect to the expression and methylation of the transgenes residing in these loci. We show that in an IR locus, the transgenes located proximal to the IR center are much more highly methylated than are the distal genes. A strong silencing locus composed of three inverted T-DNAs bearing promoterless Chs transgenes was methylated across the entire locus. The host Chs genes in untransformed plants were moderately methylated, and no change in methylation was detected when the genes were silenced. Run-on transcription assays showed that promoter-driven transgenes located proximal to the center of a particular IR are transcriptionally more repressed than are the distal genes of the same IR locus. Transcription of the promoterless Chs transgenes could not be detected. In the primary transformant, some of the IR loci were detected together with an unlinked S locus. We observed that the methylation and expression characteristics of the transgenes of these S loci were comparable to those of the partner IR loci, suggesting that there has been cross talk between the two types of loci. Despite the similar features, S loci are unable to induce silencing, indicating that the palindromic arrangement of the Chs transgenes in the IR loci is critical for silencing. Since transcriptionally silenced transgenes in IRs can trigger posttranscriptional silencing of the host genes, our data are most consistent with a model of silencing in which the transgenes physically interact with the

  12. CB1 receptor antagonism increases hippocampal acetylcholine release: site and mechanism of action.

    Science.gov (United States)

    Degroot, Aldemar; Köfalvi, Attila; Wade, Mark R; Davis, Richard J; Rodrigues, Ricardo J; Rebola, Nelson; Cunha, Rodrigo A; Nomikos, George G

    2006-10-01

    Evidence indicates that blockade of cannabinoid receptors increases acetylcholine (ACh) release in brain cortical regions. Although it is assumed that this type of effect is mediated through CB1 receptor (CB1R) antagonism, several in vitro functional studies recently have suggested non-CB1R involvement. In addition, neither the precise neuroanatomical site nor the exact mechanisms underlying this effect are known. We thoroughly examined these issues using a combination of systemic and local administration of CB1R antagonists, different methods of in vivo microdialysis, CB1R knockout (KO) mice, tissue measurements of ACh, and immunochemistry. First, we showed that systemic injections of the CB1R antagonists N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboximide hydrochloride (SR-141716A) and N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2, 4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251) dose-dependently increased hippocampal ACh efflux. Likewise, local hippocampal, but not septal, infusions of SR141716A or AM251 increased hippocampal ACh release. It is noteworthy that the stimulatory effects of systemically administered CB1R antagonists on hippocampal ACh release were completely abolished in CB1R KO mice. CB1R KO mice had similar basal but higher stress-enhanced hippocampal ACh levels compared with wild-type controls. It is interesting that dopamine D1 receptor antagonism counteracted the stimulatory effect of CB1R blockade on hippocampal ACh levels. Finally, immunohistochemical methods revealed that a high proportion of CB1R-positive nerve terminals were found in hippocampus and confirmed the colocalization of CB1 receptors with cholinergic and dopaminergic nerve terminals. In conclusion, hippocampal ACh release may specifically be controlled through CB1Rs located on both cholinergic and dopaminergic neuronal projections, and CB1R antagonism increases hippocampal ACh release, probably through both a direct

  13. Simultaneous silencing of multiple genes in the apple scab fungus, Venturia inaequalis, by expression of RNA with chimeric inverted repeats

    NARCIS (Netherlands)

    Fitzgerald, A.; Kan, van J.A.L.; Plummer, K.M.

    2004-01-01

    RNA-mediated gene silencing has been demonstrated in plants, animals, and more recently in filamentous fungi. Here, we report high frequency, RNA-mediated gene silencing in the apple scab fungus, Venturia inaequalis. The green fluorescent protein (GFP) transgene was silenced in a GFP-expressing

  14. Ways to Promote the Classroom Participation of International Students by Understanding the Silence of Japanese University Students

    Science.gov (United States)

    Kim, Soonhyang; Ates, Burcu; Grigsby, Yurimi; Kraker, Stefani; Micek, Timothy A.

    2016-01-01

    The authors explored the role of silence and deciphered its meaning and usefulness as a teaching and learning strategy for Japanese students through a survey of Japanese university students in their home country. This study has revealed that participant responses were evenly divided among comfortable with silence, uncomfortable with silence, and…

  15. Dickkopf-Related Protein 2 is Epigenetically Inactivated and Suppresses Colorectal Cancer Growth and Tumor Metastasis by Antagonizing Wnt/β-Catenin Signaling

    Directory of Open Access Journals (Sweden)

    Can Wang

    2017-03-01

    Full Text Available Background/Aims: Aberrant activation of the Wnt/β-catenin signaling pathway plays a key role in the pathogenesis of multiple tumors including digestive cancers. Recent studies have reported that Dickkopf-related protein 2 (DKK2 is epigenetically inactivated in numerous types of cancers and that its gene products exhibit tumor-suppressive properties. However, the biological functions and underlying molecular mechanisms of DKK2 in colon carcinoma remains obscure. Methods: We examined the expression of DKK2 in colon tumor cell lines by RT-PCR and its promoter methylation status in colon tumor cell lines and primary tumors by methylation-specific PCR (MSP. Ectopic expression of DKK2 was measured by RT-PCR prior to the other experiments. To investigate the function of DKK2, we assayed colony formation and cell proliferation, utilized flow cytometric analyses of the cell cycle and acridine orange/ethidium bromide (AO/EB fluorescence staining for apoptosis, and examined wound healing, transwell migration and tumor growth in vivo. Western blots were used to explore the mechanisms of DKK2 in epithelial- mesenchymal transition and canonical Wnt/β-catenin signaling. Results: We show here that downregulation or silencing of DKK2 was closely associated with the hypermethylation status of its promoter and that DKK2 expression could be restored by demethylation treatment. Methylation of the DKK2 promoter was detected in nearly all tumors and tumor-adjacent tissues, but not in normal colon tissues. Ectopic expression of DKK2 in colon cell lines HCT116 and HT-29 inhibited colony formation and cell viability by inducing cell cycle G0/G1 arrest and apoptosis, and growth of stable DKK2-infected HCT116 cells in nude mice was decreased compared to controls. Furthermore, DKK2 restrained cell migration through partial reversal of epithelial-to- mesenchymal transition and also by downregulating several stem cell markers. Our data further showed that restoration of DKK

  16. The human HECA interacts with cyclins and CDKs to antagonize Wnt-mediated proliferation and chemoresistance of head and neck cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Dowejko, Albert, E-mail: Albert.Dowejko@klinik.uni-regensburg.de [Department of Oral and Maxillofacial Surgery, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg (Germany); Bauer, Richard; Bauer, Karin [Department of Oral and Maxillofacial Surgery, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg (Germany); Mueller-Richter, Urs D.A. [Department of Oral and Maxillofacial Plastic Surgery, University of Wuerzburg, Pleicherwall 2, 97070 Wuerzburg (Germany); Reichert, Torsten E. [Department of Oral and Maxillofacial Surgery, University Hospital Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg (Germany)

    2012-03-10

    There is a growing evidence that the human homologue of the Drosophila headcase (HECA) plays an important role in human carcinogenesis. So far specific protein interaction partners and affected signaling pathways of HECA are still elusive. In a recent study we showed that HECA overexpression in oral squamous-cell carcinoma (OSCC) keratinocytes has tumor suppressive effects resulting in a recuperation of cell cycle control concerning the entry and progression of S-phase, G2- and M-phase. Currently, quantitative RT-PCR and immunohistochemical analysis of primary tumor tissue from OSCC patients demonstrate that HECA expression is markedly decreased compared to normal control patients with abundant HECA expression. Additionally, there is nearly no HECA expression in OSCC metastases. Here, we show that HECA expression is negatively controlled by the Wnt-pathway and TCF4, a Wnt related transcription factor, binds to the HECA promoter. Furthermore, immunocytochemistry reveals colocalization of HECA with the cyclin dependent kinase CDK9. Immunoprecipitation experiments and proximity ligation assays further reveal an interaction of HECA with CDK2, CDK9, Cyclin A and Cyclin K, a direct transcriptional target of the p53 tumor suppressor. Silencing HECA in OSCC cell lines leads to a significant increase of cell division and a markedly increased resistance against the chemotherapeutic cisplatin. On the contrary, HECA overexpressing OSCC cell lines show decreased resistance of OSCC cells against cisplatin. Therefore, HECA could be considered as future therapeutic agent against Wnt-dependent tumor progression. -- Highlights: Black-Right-Pointing-Pointer HECA is a new cell cycle regulator with anti-tumor features in head and neck cancer. Black-Right-Pointing-Pointer During tumor progression HECA mRNA and protein expression decrease. Black-Right-Pointing-Pointer The HECA promotor is a direct target of the Wnt/beta-catenin/TCF-pathway. Black-Right-Pointing-Pointer The HECA protein

  17. Transcription Factor Antagonism Controls Enteroendocrine Cell Specification from Intestinal Stem Cells.

    Science.gov (United States)

    Li, Yumei; Pang, Zhimin; Huang, Huanwei; Wang, Chenhui; Cai, Tao; Xi, Rongwen

    2017-04-20

    The balanced maintenance and differentiation of local stem cells is required for Homeostatic renewal of tissues. In the Drosophila midgut, the transcription factor Escargot (Esg) maintains undifferentiated states in intestinal stem cells, whereas the transcription factors Scute (Sc) and Prospero (Pros) promote enteroendocrine cell specification. However, the mechanism through which Esg and Sc/Pros coordinately regulate stem cell differentiation is unknown. Here, by combining chromatin immunoprecipitation analysis with genetic studies, we show that both Esg and Sc bind to a common promoter region of pros. Moreover, antagonistic activity between Esg and Sc controls the expression status of Pros in stem cells, thereby, specifying whether stem cells remain undifferentiated or commit to enteroendocrine cell differentiation. Our study therefore reveals transcription factor antagonism between Esg and Sc as a novel mechanism that underlies fate specification from intestinal stem cells in Drosophila.

  18. FoxO3A promotes metabolic adaptation to hypoxia by antagonizing Myc function

    DEFF Research Database (Denmark)

    Jensen, Kim Steen; Binderup, Tina; Jensen, Klaus Thorleif

    2011-01-01

    Exposure of metazoan organisms to hypoxia engages a metabolic switch orchestrated by the hypoxia-inducible factor 1 (HIF-1). HIF-1 mediates induction of glycolysis and active repression of mitochondrial respiration that reduces oxygen consumption and inhibits the production of potentially harmful...... reactive oxygen species (ROS). Here, we show that FoxO3A is activated in hypoxia downstream of HIF-1 and mediates the hypoxic repression of a set of nuclear-encoded mitochondrial genes. FoxO3A is required for hypoxic suppression of mitochondrial mass, oxygen consumption, and ROS production and promotes...... cell survival in hypoxia. FoxO3A is recruited to the promoters of nuclear-encoded mitochondrial genes where it directly antagonizes c-Myc function via a mechanism that does not require binding to the consensus FoxO recognition element. Furthermore, we show that FoxO3A is activated in human hypoxic...

  19. Impairments of exploration and memory after systemic or prelimbic D1-receptor antagonism in rats

    DEFF Research Database (Denmark)

    Clausen, Bettina; Schachtman, Todd R.; Mark, Louise T.

    2011-01-01

    , was administered to rats via routes that either did or did not affect spontaneous exploration: systemic or prelimbic administration, respectively. Effects were tested in spatial and non-spatial memory tasks selected for their requirements for self-initiated exploration of stimuli to be remembered in order...... to examine the effects on memory: cross-maze and object recognition task. Systemic administration reduced spatial exploration in cross-maze as well as in an open field test, and also reduced object exploration. Spatial (hippocampus-dependent) short-term memory was inhibited in the cross-maze and non......D1-receptor antagonism is known to impair rodent memory but also inhibits spontaneous exploration of stimuli to be remembered. Hypo-exploration could contribute to impaired memory by influencing event processing. In order to explore this effect, the D1 receptor antagonist, SCH23390...

  20. UV-B detected by the UVR8 photoreceptor antagonizes auxin signaling and plant shade avoidance.

    Science.gov (United States)

    Hayes, Scott; Velanis, Christos N; Jenkins, Gareth I; Franklin, Keara A

    2014-08-12

    Plants detect different facets of their radiation environment via specific photoreceptors to modulate growth and development. UV-B is perceived by the photoreceptor UV RESISTANCE LOCUS 8 (UVR8). The molecular mechanisms linking UVR8 activation to plant growth are not fully understood, however. When grown in close proximity to neighboring vegetation, shade-intolerant plants initiate dramatic stem elongation to overtop competitors. Here we show that UV-B, detected by UVR8, provides an unambiguous sunlight signal that inhibits shade avoidance responses in Arabidopsis thaliana by antagonizing the phytohormones auxin and gibberellin. UV-B triggers degradation of the transcription factors PHYTOCHROME INTERACTING FACTOR 4 and PHYTOCHROME INTERACTING FACTOR 5 and stabilizes growth-repressing DELLA proteins, inhibiting auxin biosynthesis via a dual mechanism. Our findings show that UVR8 signaling is closely integrated with other photoreceptor pathways to regulate auxin signaling and plant growth in sunlight.

  1. Neuropeptide Y Y5 receptor antagonism attenuates cocaine-induced effects in mice

    DEFF Research Database (Denmark)

    Sørensen, Gunnar; Jensen, Morten; Weikop, Pia

    2012-01-01

    Rationale Several studies suggest a role for neuropeptide Y (NPY) in addiction to drugs of abuse, including cocaine. However, the NPY receptors mediating addiction-related effects remain to be determined. Objectives To explore the potential role of Y5 NPY receptors in cocaine-induced behavioural...... effects. Methods The Y5 antagonist L-152,804 and Y5-knockout (Y5-KO) mice were tested in two models of cocaine addiction-related behaviour: acute self-administration and cocaine-induced hyperactivity. We also studied effects of Y5 receptor antagonism on cocaine-induced c-fos expression and extracellular...... dopamine with microdialysis as well as dopamine transporter-mediated uptake of dopamine in vitro. Immunocytochemistry was used to determine whether dopamine neurons express Y5-like immunoreactivity. Results In self-administration, L-152,804 prominently decreased nose-poking for the peak dose of cocaine...

  2. Dual Allosteric Effect in Glycine/NMDA Receptor Antagonism: A Comparative QSAR Approach

    Directory of Open Access Journals (Sweden)

    Vipin B. Gupta

    2010-10-01

    Full Text Available A comparative Hantzsch type QSAR study was conducted using multiple regression analysis on various sets of quinoxalines, quinoxalin-4-ones, quinazoline-2-carboxylates, 4-hydroxyquinolin-2(1H-ones, 2-carboxytetrahydroquinolines, phenyl-hydroxy-quinolones, nitroquinolones and 4-substituted-3-phenylquinolin-2(1H-ones as selective glycine/NMDA site antagonists. Ten statistically validated equations were developed, which indicated the importance of CMR, Verloop’s sterimol L1 and ClogP parameters in contributing towards biological activity. Interestingly, normal and inverse parabolic relationships were found with CMR in different series, indicating a dual allosteric binding mode in glycine/NMDA antagonism. Equations reveal an optimum CMR of 10 ± 10% is required for good potency of antagonists. Other equations indicate the presence of anionic functionality at 4-position of quinoline/quinolone ring system is not absolutely required for effective binding. The observations are laterally validated and in accordance with previous studies.

  3. USP10 Antagonizes c-Myc Transcriptional Activation through SIRT6 Stabilization to Suppress Tumor Formation

    Directory of Open Access Journals (Sweden)

    Zhenghong Lin

    2013-12-01

    Full Text Available The reduced protein expression of SIRT6 tumor suppressor is involved in tumorigenesis. The molecular mechanisms underlying SIRT6 protein downregulation in human cancers remain unknown. Using a proteomic approach, we have identified the ubiquitin-specific peptidase USP10, another tumor suppressor, as one of the SIRT6-interacting proteins. USP10 suppresses SIRT6 ubiquitination to protect SIRT6 from proteasomal degradation. USP10 antagonizes the transcriptional activity of the c-Myc oncogene through SIRT6, as well as p53, to inhibit cell-cycle progression, cancer cell growth, and tumor formation. To support this conclusion, we detected significant reductions in both USP10 and SIRT6 protein expression in human colon cancers. Our study discovered crosstalk between two tumor-suppressive genes in regulating cell-cycle progression and proliferation and showed that dysregulated USP10 function promotes tumorigenesis through SIRT6 degradation.

  4. Combining climate and energy policies: synergies or antagonism? Modeling interactions with energy efficiency instruments

    International Nuclear Information System (INIS)

    Lecuyer, Oskar; Bibas, Ruben

    2012-01-01

    In addition to the already present Climate and Energy package, the European Union (EU) plans to include a binding target to reduce energy consumption. We analyze the rationales the EU invokes to justify such an overlapping and develop a minimal common framework to study interactions arising from the combination of instruments reducing emissions, promoting renewable energy (RE) production and reducing energy demand through energy efficiency (EE) investments. We find that although all instruments tend to reduce GHG emissions and although a price on carbon tends also to give the right incentives for RE and EE, the combination of more than one instrument leads to significant antagonisms regarding major objectives of the policy package. The model allows to show in a single framework and to quantify the antagonistic effects of the joint promotion of RE and EE. We also show and quantify the effects of this joint promotion on ETS permit price, on wholesale market price and on energy production levels. (authors)

  5. What Do Structures Tell Us About Chemokine Receptor Function and Antagonism?

    Energy Technology Data Exchange (ETDEWEB)

    Kufareva, Irina; Gustavsson, Martin; Zheng, Yi; Stephens, Bryan S.; Handel, Tracy M. (UCSD)

    2017-05-22

    Chemokines and their cell surface G protein–coupled receptors are critical for cell migration, not only in many fundamental biological processes but also in inflammatory diseases and cancer. Recent X-ray structures of two chemokines complexed with full-length receptors provided unprecedented insight into the atomic details of chemokine recognition and receptor activation, and computational modeling informed by new experiments leverages these insights to gain understanding of many more receptor:chemokine pairs. In parallel, chemokine receptor structures with small molecules reveal the complicated and diverse structural foundations of small molecule antagonism and allostery, highlight the inherent physicochemical challenges of receptor:chemokine interfaces, and suggest novel epitopes that can be exploited to overcome these challenges. The structures and models promote unique understanding of chemokine receptor biology, including the interpretation of two decades of experimental studies, and will undoubtedly assist future drug discovery endeavors.

  6. Social antagonism and socio-environmental struggles in Mexico: Body, emotions and subjectivity as a combat ground against affectation

    Directory of Open Access Journals (Sweden)

    Mina Lorena Navarro Trujillo

    2010-12-01

    Full Text Available Infront of the dispossession of common, tangible and intangible assets, is emerging a new social antagonism against extractive paradigm and the commodification of life. The relationship of body and emotions emerges as a field of fight against environmental impairment, at the same time that enables an autonomous time and space for the prefiguration of a future society.

  7. Comparison of vascular alpha(1)-adrenoceptor antagonism of tamsulosin in oral controlled absorption system (OCAS) and modified release (MR) formulations

    NARCIS (Netherlands)

    Michel, M. C.; Korstanje, C.; Krauwinkel, W.; Shear, M.; Davies, J.; Quartel, A.

    2005-01-01

    Objective: The cardiovascular a-l-adrenoceptor (AR) antagonism of the new oral controlled absorption system (OCAS) 0.4 mg tablet formulation of tamsulosin was compared with that of the modified release (MR) 0.4 mg capsule formulation in healthy male volunteers after a single dose in the fasted

  8. Self-Regulation in Early Adolescence: Relations with Mother-Son Relationship Quality and Maternal Regulatory Support and Antagonism

    Science.gov (United States)

    Moilanen, Kristin L.; Shaw, Daniel S.; Fitzpatrick, Amber

    2010-01-01

    The purpose of the current investigation was to examine relations among maternal regulatory support, maternal antagonism, and mother-son relationship quality in relation to boys' self-regulation during early adolescence. As part of a larger longitudinal study on 263 low-income, ethnically diverse boys, multiple informants and methods were used to…

  9. AT(1) antagonism and renin inhibition in mice : pivotal role of targeting angiotensin II in chronic kidney disease

    NARCIS (Netherlands)

    Fraune, Christoph; Lange, Sascha; Krebs, Christian; Hoelzel, Alexandra; Baucke, Jana; Divac, Nevena; Schwedhelm, Edzard; Streichert, Thomas; Velden, Joachim; Garrelds, Ingrid M.; Danser, A. H. Jan; Frenay, Anne-Roos; van Goor, Harry; Jankowski, Vera; Stahl, Rolf; Nguyen, Genevieve; Wenzel, Ulrich Otto

    2012-01-01

    Fraune C, Lange S, Krebs C, Holzel A, Baucke J, Divac N, Schwedhelm E, Streichert T, Velden J, Garrelds IM, Danser AH, Frenay A, van Goor H, Jankowski V, Stahl R, Nguyen G, Wenzel UO. AT(1) antagonism and renin inhibition in mice: pivotal role of targeting angiotensin II in chronic kidney disease.

  10. SSX2 is a novel DNA-binding protein that antagonizes polycomb group body formation and gene repression

    DEFF Research Database (Denmark)

    Gjerstorff, Morten Frier; Relster, Mette Marie; Greve, Katrine Buch Viden

    2014-01-01

    Polycomb group (PcG) complexes regulate cellular identity through epigenetic programming of chromatin. Here, we show that SSX2, a germline-specific protein ectopically expressed in melanoma and other types of human cancers, is a chromatin-associated protein that antagonizes BMI1 and EZH2 PcG body...

  11. Kinin B1 receptor antagonism is equally efficient as angiotensin receptor 1 antagonism in reducing renal fibrosis in experimental obstructive nephropathy, but is not additive.

    Directory of Open Access Journals (Sweden)

    Antoine eHuart

    2015-02-01

    Full Text Available Background: Renal tubulointerstitial fibrosis is the pathological hallmark of chronic kidney disease. Currently, inhibitors of the renin angiotensin system (RAS remain the sole therapy in human displaying antifibrotic properties. Further antifibrotic molecules are needed. We have recently reported that the delayed blockade of the bradykinin B1 receptor (B1R reduced the development of fibrosis in two animal models of renal fibrosis. The usefulness of new drugs also resides in outperforming the gold standards and eventually being additive or complementary to existing therapies. Methods: In this study we compared the efficacy of a B1R antagonist (B1Ra with that of an angiotensin type 1 receptor antagonist (AT1a in the unilateral ureteral obstruction (UUO model of renal fibrosis and determined whether bi-therapy presented higher efficacy than any of the drugs alone. Results: B1R antagonism was as efficient as the gold-standard AT1a treatment. However bitherapy did not improve the antifibrotic effects at the protein level. We sought for the reason of the absence of this additive effect by studying the expression of a panel of genes involved in the fibrotic process. Interestingly, at the molecular level the different drugs targeted different players of fibrosis that, however, in this severe model did not result in improved reduction of fibrosis at the protein level. Conclusions: As the B1R is induced specifically in the diseased organ and thus potentially displays low side effects it might be an interesting alternative in cases of poor tolerability to RAS inhibitors.

  12. SB-224289 Antagonizes the Antifungal Mechanism of the Marine Depsipeptide Papuamide A.

    Directory of Open Access Journals (Sweden)

    Chelsi D Cassilly

    Full Text Available In order to expand the repertoire of antifungal compounds a novel, high-throughput phenotypic drug screen targeting fungal phosphatidylserine (PS synthase (Cho1p was developed based on antagonism of the toxin papuamide A (Pap-A. Pap-A is a cyclic depsipeptide that binds to PS in the membrane of wild-type Candida albicans, and permeabilizes its plasma membrane, ultimately causing cell death. Organisms with a homozygous deletion of the CHO1 gene (cho1ΔΔ do not produce PS and are able to survive in the presence of Pap-A. Using this phenotype (i.e. resistance to Pap-A as an indicator of Cho1p inhibition, we screened over 5,600 small molecules for Pap-A resistance and identified SB-224289 as a positive hit. SB-224289, previously reported as a selective human 5-HT1B receptor antagonist, also confers resistance to the similar toxin theopapuamide (TPap-A, but not to other cytotoxic depsipeptides tested. Structurally similar molecules and truncated variants of SB-224289 do not confer resistance to Pap-A, suggesting that the toxin-blocking ability of SB-224289 is very specific. Further biochemical characterization revealed that SB-224289 does not inhibit Cho1p, indicating that Pap-A resistance is conferred by another undetermined mechanism. Although the mode of resistance is unclear, interaction between SB-224289 and Pap-A or TPap-A suggests this screening assay could be adapted for discovering other compounds which could antagonize the effects of other environmentally- or medically-relevant depsipeptide toxins.

  13. Dopamine Receptor D1 Agonism and Antagonism Using a Field-Effect Transistor Assay.

    Science.gov (United States)

    Park, Seon Joo; Yang, Heehong; Lee, Seung Hwan; Song, Hyun Seok; Park, Chul Soon; Bae, Joonwon; Kwon, Oh Seok; Park, Tai Hyun; Jang, Jyongsik

    2017-06-27

    The field-effect transistor (FET) has been used in the development of diagnostic tools for several decades, leading to high-performance biosensors. Therefore, the FET platform can provide the foundation for the next generation of analytical methods. A major role of G-protein-coupled receptors (GPCRs) is in the transfer of external signals into the cell and promoting human body functions; thus, their principle application is in the screening of new drugs. The research community uses efficient systems to screen potential GPCR drugs; nevertheless, the need to develop GPCR-conjugated analytical devices remains for next-generation new drug screening. In this study, we proposed an approach for studying receptor agonism and antagonism by combining the roles of FETs and GPCRs in a dopamine receptor D1 (DRD1)-conjugated FET system, which is a suitable substitute for conventional cell-based receptor assays. DRD1 was reconstituted and purified to mimic native binding pockets that have highly discriminative interactions with DRD1 agonists/antagonists. The real-time responses from the DRD1-nanohybrid FET were highly sensitive and selective for dopamine agonists/antagonists, and their maximal response levels were clearly different depending on their DRD1 affinities. Moreover, the equilibrium constants (K) were estimated by fitting the response levels. Each K value indicates the variation in the affinity between DRD1 and the agonists/antagonists; a greater K value corresponds to a stronger DRD1 affinity in agonism, whereas a lower K value in antagonism indicates a stronger dopamine-blocking effect.

  14. Ghrelin receptor antagonism of hyperlocomotion in cocaine-sensitized mice requires βarrestin-2.

    Science.gov (United States)

    Toth, Krisztian; Slosky, Lauren M; Pack, Thomas F; Urs, Nikhil M; Boone, Peter; Mao, Lan; Abraham, Dennis; Caron, Marc G; Barak, Lawrence S

    2018-01-01

    The "brain-gut" peptide ghrelin, which mediates food-seeking behaviors, is recognized as a very strong endogenous modulator of dopamine (DA) signaling. Ghrelin binds the G protein-coupled receptor GHSR1a, and administration of ghrelin increases the rewarding properties of psychostimulants while ghrelin receptor antagonists decrease them. In addition, the GHSR1a signals through βarrestin-2 to regulate actin/stress fiber rearrangement, suggesting βarrestin-2 participation in the regulation of actin-mediated synaptic plasticity for addictive substances like cocaine. The effects of ghrelin receptor ligands on reward strongly suggest that modulation of ghrelin signaling could provide an effective strategy to ameliorate undesirable behaviors arising from addiction. To investigate this possibility, we tested the effects of ghrelin receptor antagonism in a cocaine behavioral sensitization paradigm using DA neuron-specific βarrestin-2 KO mice. Our results show that these mice sensitize to cocaine as well as wild-type littermates. The βarrestin-2 KO mice, however, no longer respond to the locomotor attenuating effects of the GHSR1a antagonist YIL781. The data presented here suggest that the separate stages of addictive behavior differ in their requirements for βarrestin-2 and show that pharmacological inhibition of βarrestin-2 function through GHSR1a antagonism is not equivalent to the loss of βarrestin-2 function achieved by genetic ablation. These data support targeting GHSR1a signaling in addiction therapy but indicate that using signaling biased compounds that modulate βarrestin-2 activity differentially from G protein activity may be required. © 2017 Wiley Periodicals, Inc.

  15. RAB-7 antagonizes LET-23 EGFR signaling during vulva development in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Olga Skorobogata

    Full Text Available The Rab7 GTPase regulates late endosome trafficking of the Epidermal Growth Factor Receptor (EGFR to the lysosome for degradation. However, less is known about how Rab7 activity, functioning late in the endocytic pathway, affects EGFR signaling. Here we used Caenorhabditis elegans vulva cell fate induction, a paradigm for genetic analysis of EGFR/Receptor Tyrosine Kinase (RTK signaling, to assess the genetic requirements for rab-7. Using a rab-7 deletion mutant, we demonstrate that rab-7 antagonizes LET-23 EGFR signaling to a similar extent, but in a distinct manner, as previously described negative regulators such as sli-1 c-Cbl. Epistasis analysis places rab-7 upstream of or in parallel to lin-3 EGF and let-23 EGFR. However, expression of gfp::rab-7 in the Vulva Presursor Cells (VPCs is sufficient to rescue the rab-7(- VPC induction phenotypes indicating that RAB-7 functions in the signal receiving cell. We show that components of the Endosomal Sorting Complex Required for Transport (ESCRT-0, and -I, complexes, hgrs-1 Hrs, and vps-28, also antagonize signaling, suggesting that LET-23 EGFR likely transits through Multivesicular Bodies (MVBs en route to the lysosome. Consistent with RAB-7 regulating LET-23 EGFR trafficking, rab-7 mutants have increased number of LET-23::GFP-positive endosomes. Our data imply that Rab7, by mediating EGFR trafficking and degradation, plays an important role in downregulation of EGFR signaling. Failure to downregulate EGFR signaling contributes to oncogenesis, and thus Rab7 could possess tumor suppressor activity in humans.

  16. Genomic agonism and phenotypic antagonism between estrogen and progesterone receptors in breast cancer.

    Science.gov (United States)

    Singhal, Hari; Greene, Marianne E; Tarulli, Gerard; Zarnke, Allison L; Bourgo, Ryan J; Laine, Muriel; Chang, Ya-Fang; Ma, Shihong; Dembo, Anna G; Raj, Ganesh V; Hickey, Theresa E; Tilley, Wayne D; Greene, Geoffrey L

    2016-06-01

    The functional role of progesterone receptor (PR) and its impact on estrogen signaling in breast cancer remain controversial. In primary ER(+) (estrogen receptor-positive)/PR(+) human tumors, we report that PR reprograms estrogen signaling as a genomic agonist and a phenotypic antagonist. In isolation, estrogen and progestin act as genomic agonists by regulating the expression of common target genes in similar directions, but at different levels. Similarly, in isolation, progestin is also a weak phenotypic agonist of estrogen action. However, in the presence of both hormones, progestin behaves as a phenotypic estrogen antagonist. PR remodels nucleosomes to noncompetitively redirect ER genomic binding to distal enhancers enriched for BRCA1 binding motifs and sites that link PR and ER/PR complexes. When both hormones are present, progestin modulates estrogen action, such that responsive transcriptomes, cellular processes, and ER/PR recruitment to genomic sites correlate with those observed with PR alone, but not ER alone. Despite this overall correlation, the transcriptome patterns modulated by dual treatment are sufficiently different from individual treatments, such that antagonism of oncogenic processes is both predicted and observed. Combination therapies using the selective PR modulator/antagonist (SPRM) CDB4124 in combination with tamoxifen elicited 70% cytotoxic tumor regression of T47D tumor xenografts, whereas individual therapies inhibited tumor growth without net regression. Our findings demonstrate that PR redirects ER chromatin binding to antagonize estrogen signaling and that SPRMs can potentiate responses to antiestrogens, suggesting that cotargeting of ER and PR in ER(+)/PR(+) breast cancers should be explored.

  17. Distinct effects of estrogen receptor antagonism on object recognition and spatial memory consolidation in ovariectomized mice.

    Science.gov (United States)

    Kim, Jaekyoon; Frick, Karyn M

    2017-11-01

    Exogenous treatment with the potent estrogen 17β-estradiol (E 2 ) or selective estrogen receptor α/β (ERα/β) agonists enhances the consolidation of hippocampal-dependent object recognition (OR) and object placement (OP) memories in ovariectomized rodents. Although such data suggest that individual ERs are sufficient for memory consolidation, the necessity of a given ER for memory consolidation can only be demonstrated by blocking receptor function, for example with an ER antagonist. However, the effects on memory of antagonizing ERα or ERβ function are not well understood. Moreover, ER antagonism in ovariectomized subjects also provides indirect information about the role of individual ERs in the memory-enhancing effects of local hippocampal E 2 synthesis. Therefore, this study used pharmacological inhibition of ERα and ERβ to elucidate the importance of each ER to memory consolidation. Specifically, we examined effects on OR and OP memory consolidation of immediate post-training dorsal hippocampal (DH) infusion of MPP and PHTPP, selective antagonists for ERα and ERβ, respectively. Each drug exhibited a distinct effect on OR and OP. DH infusion of MPP (0.28 or 2.78ng/hemisphere) impaired memory in OP, but not OR. However, DH infusion of PHTPP (0.21 or 2.12ng/hemisphere) impaired memory in both OR and OP. Neither drug affected the elapsed time to accumulate object exploration in either task, suggesting a specific effect on memory. These results indicate that activation of either classical ER within the dorsal hippocampus is important for hippocampal memory consolidation in ovariectomized mice, but suggest that specific ER involvement is memory- or task-specific. The findings also indirectly support a role for ERα and ERβ in mediating the memory-enhancing effects of hippocampally-synthesized E 2 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Adaptation of the Four Forms of Employee Silence Scale in a Polish sample

    Directory of Open Access Journals (Sweden)

    Krystyna Adamska

    2017-06-01

    Full Text Available Background Silence is understood as a decision not to speak up in situations of observed irregularities both in productivity and ethics. The study examined the validity of the Four Forms of Employee Silence Scale (FFESS in the Polish population. The scale is a four-factor measure designed to capture differently motivated tendencies to be silent in organizations. The scale distinguishes acquiescent, quiescent, prosocial and opportunistic silence. Employee silence has been linked to many important individual outcomes: failure to react to ethical transgressions, stress and depression, and lower creativity and productivity. Participants and procedure A total of 1044 employees of various organizations working for at least six months at a given position provided the responses for the validation study. Results The results confirmed the superiority of the four-factor model shown by adequate fit indexes: The FFESS has adequate internal consistency at both the scale and item levels. The criterion-related validity of the scale was established by correlating four forms of silence with measures of emotional attitude toward organization, procedural justice, relational contract and turnover intention. Conclusions The four forms of employee silence are empirically distinct concepts in the Polish sample. The scale may be used as the measurement of individual differences. It can also serve as a tool for diagnosing a climate of silence in an organization.

  19. RNA Silencing in Plants: Mechanisms, Technologies and Applications in Horticultural Crops.

    Science.gov (United States)

    Guo, Qigao; Liu, Qing; Smith, Neil A; Liang, Guolu; Wang, Ming-Bo

    2016-12-01

    Understanding the fundamental nature of a molecular process or a biological pathway is often a catalyst for the development of new technologies in biology. Indeed, studies from late 1990s to early 2000s have uncovered multiple overlapping but functionally distinct RNA silencing pathways in plants, including the posttranscriptional microRNA and small interfering RNA pathways and the transcriptional RNA-directed DNA methylation pathway. These findings have in turn been exploited for developing artificial RNA silencing technologies such as hairpin RNA, artificial microRNA, intrinsic direct repeat, 3' UTR inverted repeat, artificial trans-acting siRNA, and virus-induced gene silencing technologies. Some of these RNA silencing technologies, such as the hairpin RNA technology, have already been widely used for genetic improvement of crop plants in agriculture. For horticultural plants, RNA silencing technologies have been used to increase disease and pest resistance, alter plant architecture and flowering time, improve commercial traits of fruits and flowers, enhance nutritional values, remove toxic compounds and allergens, and develop high-value industrial products. In this article we aim to provide an overview of the RNA silencing pathways in plants, summarize the existing RNA silencing technologies, and review the current progress in applying these technologies for the improvement of agricultural crops particularly horticultural crops.

  20. A translational silencing function of MCPIP1/Regnase-1 specified by the target site context.

    Science.gov (United States)

    Behrens, Gesine; Winzen, Reinhard; Rehage, Nina; Dörrie, Anneke; Barsch, Monika; Hoffmann, Anne; Hackermüller, Jörg; Tiedje, Christopher; Heissmeyer, Vigo; Holtmann, Helmut

    2018-02-19

    The expression of proteins during inflammatory and immune reactions is coordinated by post-transcriptional mechanisms. A particularly strong suppression of protein expression is exerted by a conserved translational silencing element (TSE) identified in the 3' UTR of NFKBIZ mRNA, which is among the targets of the RNA-binding proteins Roquin-1/2 and MCPIP1/Regnase-1. We present evidence that in the context of the TSE MCPIP1, so far known for its endonuclease activity toward mRNAs specified by distinct stem-loop (SL) structures, also suppresses translation. Overexpression of MCPIP1 silenced translation in a TSE-dependent manner and reduced ribosome occupancy of the mRNA. Correspondingly, MCPIP1 depletion alleviated silencing and increased polysomal association of the mRNA. Translationally silenced NFKBIZ or reporter mRNAs were mostly capped, polyadenylated and ribosome associated. Furthermore, MCPIP1 silenced also cap-independent, CrPV-IRES-dependent translation. This suggests that MCPIP1 suppresses a post-initiation step. The TSE is predicted to form five SL structures. SL4 and 5 resemble target structures reported for MCPIP1 and together were sufficient for MCPIP1 binding and mRNA destabilization. Translational silencing, however, required SL1-3 in addition. Thus the NFKBIZ TSE functions as an RNA element in which sequences adjacent to the site of interaction with MCPIP1 and dispensable for accelerated mRNA degradation extend the functional repertoire of MCPIP1 to translational silencing.

  1. Generosity or genocide? Identity implications of silence in American Thanksgiving commemorations.

    Science.gov (United States)

    Kurtiş, Tuğçe; Adams, Glenn; Bird, Michael Yellow

    2010-02-01

    This paper investigates the identity implications of silence about genocide in commemorations of American Thanksgiving. In Study 1 we assessed the co-occurrence of national glorification themes with different forms of silence in commemoration products by conducting a content analysis of presidential Thanksgiving proclamations. In Study 2 we examined the extent to which different commemoration products are infused with particular beliefs and desires by measuring participants' reactions to different Thanksgiving commemorations-a literal-silence condition that did not mention Indigenous Peoples, an interpretive-silence condition that mentioned Indigenous Peoples but did not explicitly mention genocidal conquest, and an anti-silence condition that did mention genocidal conquest-as a function of national glorification. In Study 3 we manipulated exposure to different Thanksgiving commemorations (with associated forms of silence) and assessed the impact on national glorification and identity-relevant action. Results provide evidence for the hypothesised, bi-directional relationship between national glorification and silence about genocide in commemorations of American Thanksgiving.

  2. Language matters: towards an understanding of silence and humour in medical education.

    Science.gov (United States)

    Lingard, Lorelei

    2013-01-01

    This paper considers the state of the science regarding language matters in medical education, with particular attention to two informal language practices: silence and humour. Silence and humour pervade clinical training settings, although we rarely attend explicitly to them. This paper considers the treatment of these topics in our field to date and introduces a selection of the scholarship on silence and humour from other fields, including philosophy, sociology, anthropology, linguistics and rhetoric. Particular attention is paid to distilling the theoretical and methodological possibilities for an elaborated research agenda around silence and humour in medical education. These two language practices assume a variety of forms and serve a range of social functions. Episodes of silence and humour are intimately tied to their relational and institutional contexts. Power often figures centrally, although not predictably. A rich theoretical and methodological basis exists on which to elaborate a research agenda around silence and humour in medical education. Such research promises to reveal more fully the contributions of silence and humour to socialisation in clinical training settings. © Blackwell Publishing Ltd 2013.

  3. RNA-Interference Components Are Dispensable for Transcriptional Silencing of the Drosophila Bithorax-Complex

    KAUST Repository

    Cernilogar, Filippo M.

    2013-06-13

    Background:Beyond their role in post-transcriptional gene silencing, Dicer and Argonaute, two components of the RNA interference (RNAi) machinery, were shown to be involved in epigenetic regulation of centromeric heterochromatin and transcriptional gene silencing. In particular, RNAi mechanisms appear to play a role in repeat induced silencing and some aspects of Polycomb-mediated gene silencing. However, the functional interplay of RNAi mechanisms and Polycomb group (PcG) pathways at endogenous loci remains to be elucidated.Principal Findings:Here we show that the endogenous Dicer-2/Argonaute-2 RNAi pathway is dispensable for the PcG mediated silencing of the homeotic Bithorax Complex (BX-C). Although Dicer-2 depletion triggers mild transcriptional activation at Polycomb Response Elements (PREs), this does not induce transcriptional changes at PcG-repressed genes. Moreover, Dicer-2 is not needed to maintain global levels of methylation of lysine 27 of histone H3 and does not affect PRE-mediated higher order chromatin structures within the BX-C. Finally bioinformatic analysis, comparing published data sets of PcG targets with Argonaute-2-bound small RNAs reveals no enrichment of these small RNAs at promoter regions associated with PcG proteins.Conclusions:We conclude that the Dicer-2/Argonaute-2 RNAi pathway, despite its role in pairing sensitive gene silencing of transgenes, does not have a role in PcG dependent silencing of major homeotic gene cluster loci in Drosophila. © 2013 Cernilogar et al.

  4. The Luteovirus P4 Movement Protein Is a Suppressor of Systemic RNA Silencing.

    Science.gov (United States)

    Fusaro, Adriana F; Barton, Deborah A; Nakasugi, Kenlee; Jackson, Craig; Kalischuk, Melanie L; Kawchuk, Lawrence M; Vaslin, Maite F S; Correa, Regis L; Waterhouse, Peter M

    2017-10-10

    The plant viral family Luteoviridae is divided into three genera: Luteovirus , Polerovirus and Enamovirus . Without assistance from another virus, members of the family are confined to the cells of the host plant's vascular system. The first open reading frame (ORF) of poleroviruses and enamoviruses encodes P0 proteins which act as silencing suppressor proteins (VSRs) against the plant's viral defense-mediating RNA silencing machinery. Luteoviruses, such as barley yellow dwarf virus-PAV (BYDV-PAV), however, have no P0 to carry out the VSR role, so we investigated whether other proteins or RNAs encoded by BYDV-PAV confer protection against the plant's silencing machinery. Deep-sequencing of small RNAs from plants infected with BYDV-PAV revealed that the virus is subjected to RNA silencing in the phloem tissues and there was no evidence of protection afforded by a possible decoy effect of the highly abundant subgenomic RNA3. However, analysis of VSR activity among the BYDV-PAV ORFs revealed systemic silencing suppression by the P4 movement protein, and a similar, but weaker, activity by P6. The closely related BYDV-PAS P4, but not the polerovirus potato leafroll virus P4, also displayed systemic VSR activity. Both luteovirus and the polerovirus P4 proteins also showed transient, weak local silencing suppression. This suggests that systemic silencing suppression is the principal mechanism by which the luteoviruses BYDV-PAV and BYDV-PAS minimize the effects of the plant's anti-viral defense.

  5. Apparent ploidy effects on silencing are post-transcriptional at HML and telomeres in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Jenny M McLaughlan

    Full Text Available The repression of genes in regions of heterochromatin is known as transcriptional silencing. It occurs in a wide range of organisms and can have importance in adaptation to the environment, developmental changes and disease. The model organism Saccharomyces cerevisiae has been used for many years to study transcriptional silencing, but until recently no study has been made in relation to ploidy. The aim of this work was to compare transcriptional silencing in haploids and diploids at both telomeres and the hidden mating-type (HM loci. Transcriptional silencing was assayed, by growth on 5-fluoroorotic acid (5-FOA media or by flow cytometry, on strains where a telomere or HM locus was marked. RNA levels were measured by quantitative RT-PCR to confirm that effects were transcriptional. 5-FOA assays and flow cytometry were consistent with transcriptional silencing at telomeres and at HML being reduced as ploidy increases which agreed with conclusions in previous publications. However, QRT-PCR revealed that transcriptional silencing was unaffected by ploidy and thus protein levels were increasing independently of RNA levels. At telomere XI left (XI-L, changes in protein level were strongly influenced by mating-type, whereas at HML mating-type had much less influence. The post-transcriptional effects seen in this study, illustrate the often ignored need to measure RNA levels when assaying transcriptional silencing in Saccharomyces cerevisiae.

  6. Lack of pairing during meiosis triggers multigenerational transgene silencing in Caenorhabditis elegans

    Science.gov (United States)

    Leopold, Luciana E.; Heestand, Bree N.; Seong, Soobin; Shtessel, Ludmila; Ahmed, Shawn

    2015-01-01

    Single-copy transgenes in Caenorhabditis elegans can be subjected to a potent, irreversible silencing process termed small RNA-induced epigenetic silencing (RNAe). RNAe is promoted by the Piwi Argonaute protein PRG-1 and associated Piwi-interacting RNAs (piRNAs), as well as by proteins that promote and respond to secondary small interfering RNA (siRNA) production. Here we define a related siRNA-mediated silencing process, termed “multigenerational RNAe,” which can occur for transgenes that are maintained in a hemizygous state for several generations. We found that transgenes that contain either GFP or mCherry epitope tags can be silenced via multigenerational RNAe, whereas a transgene that possesses GFP and a perfect piRNA target site can be rapidly and permanently silenced via RNAe. Although previous studies have shown that PRG-1 is typically dispensable for maintenance of RNAe, we found that both initiation and maintenance of multigenerational RNAe requires PRG-1 and the secondary siRNA biogenesis protein RDE-2. Although silencing via RNAe is irreversible, we found that transgene expression can be restored when hemizygous transgenes that were silenced via multigenerational RNAe become homozygous. Furthermore, multigenerational RNAe was accelerated when meiotic pairing of the chromosome possessing the transgene was abolished. We propose that persistent lack of pairing during meiosis elicits a reversible multigenerational silencing response, which can lead to permanent transgene silencing. Multigenerational RNAe may be broadly relevant to single-copy transgenes used in experimental biology and to shaping the epigenomic landscape of diverse species, where genomic polymorphisms between homologous chromosomes commonly result in unpaired DNA during meiosis. PMID:25941370

  7. 5-Azacytidine mediated reactivation of silenced transgenes in potato (Solanum tuberosum) at the whole plant level.

    Science.gov (United States)

    Tyč, Dimitrij; Nocarová, Eva; Sikorová, Lenka; Fischer, Lukáš

    2017-08-01

    Transient 5-azacytidine treatment of leaf explants from potato plants with transcriptionally silenced transgenes allows de novo regeneration of plants with restored transgene expression at the whole plant level. Transgenes introduced into plant genomes frequently become silenced either at the transcriptional or the posttranscriptional level. Transcriptional silencing is usually associated with DNA methylation in the promoter region. Treatments with inhibitors of maintenance DNA methylation were previously shown to allow reactivation of transcriptionally silenced transgenes in single cells or tissues, but not at the whole plant level. Here we analyzed the effect of DNA methylation inhibitor 5-azacytidine (AzaC) on the expression of two silenced reporter genes encoding green fluorescent protein (GFP) and neomycin phosphotransferase (NPTII) in potato plants. Whereas no obvious reactivation was observed in AzaC-treated stem cuttings, transient treatment of leaf segments with 10 μM AzaC and subsequent de novo regeneration of shoots on the selective medium with kanamycin resulted in the production of whole plants with clearly reactivated expression of previously silenced transgenes. Reactivation of nptII expression was accompanied by a decrease in cytosine methylation in the promoter region of the gene. Using the plants with reactivated GFP expression, we found that re-silencing of this transgene can be accidentally triggered by de novo regeneration. Thus, testing the incidence of transgene silencing during de novo regeneration could be a suitable procedure for negative selection of transgenic lines (insertion events) which have an inclination to be silenced. Based on our analysis of non-specific inhibitory effects of AzaC on growth of potato shoots in vitro, we estimated that AzaC half-life in the culture media is approximately 2 days.

  8. The effect of acid-base balance on neostigmine antagonism of d-tubocurarine-induced neuromuscular blockade.

    Science.gov (United States)

    Miller, R D; Van Nyhuis, L S; Eger, E I; Way, W L

    1975-04-01

    d-Tubocurarine (dTc) was infused intravenously into 35 cats anesthetized with chloralose and urethane at a constant continuous rate to produce and maintain 90 per cent depression of twitch height of the anterior tibial muscle following supramaximal stimulation of the peroneal nerve. The mean infusion rates that produced 90 per cent depression were not significantly altered by respiratory acid-base changes. Metabolic alkalosis decreased (32.5 per cent) and metabolic acidosis increased (27.7 per cent) the required infusion rate of dTc. When pH and Paco2 were maintained at 7.37 and 38 torr, respectively, the addition of a bolus of neostigmine, 10.5 mug/kg, intravenously, to the continuing infusion of dTc produced 50 per cent antagonism of the dTc-depressed twitch. Respiratory alkalosis and metabolic acidosis did not alter the dose of neostigmine needed to produce 50 per cent antagonism. However, during respiratory acidosis (pH 7.13, Paco2 66 torr) and metabolic alkalosis (pH 7.59, Paco2 36 torr) 20.0 and 18.0 mug/kg neostigmine, respectively, were needed to produce 50 per cent antagonism. Still larger doses of neostigmine (75 mug/kg) could not completely antagonize the block unless pH and Paco2 were returned to 7.30-7.50 and 35-45 torr, respectively. It is concluded that respiratory acidosis and metabolic alkalosis limit and oppose antagonism of dTc by neostigmine.

  9. Driving in unheard silence: Disability and the politics of shutting up.

    Science.gov (United States)

    Lourens, Heidi

    2018-03-01

    The politics of silence is central to disability experience and the field of disability studies. In this analytical autoethnography, I write about my silences as a visually impaired woman. I explore and make sense of personal life stories through a theoretical perspective. The analysis of these personal experiences lead me to argue that disability-related silences are mostly created through the confluence of inaccessible physical and social environments and the psychological internalisation of these worlds. I also discuss the ways in which I am currently regaining my voice. Further research on resistance by disabled persons is recommended.

  10. Empathy and silence in pastoral care for traumatic grief and loss.

    Science.gov (United States)

    Capretto, Peter

    2015-02-01

    This paper evaluates silence as a therapeutic practice in pastoral care for traumatic grief and loss. Informed by the history of attachment and mourning theory, its research considers the basic effect that empathy has upon the therapeutic relationship around psychic difference. The study appraises the potential resources and detriments that empathic language may have for the grief process. Offering clinical examples in hospice chaplaincy, it refutes the idea that silence is formulaic tool to be used. It instead offers silence as the acceptance of the limits of empathic language and the affirmation of psychological difference and theological wholeness.

  11. Silence as an element of care: A meta-ethnographic review of professional caregivers' experience in clinical and pastoral settings.

    Science.gov (United States)

    Bassett, Lynn; Bingley, Amanda F; Brearley, Sarah G

    2018-01-01

    In interactions between professional caregivers, patients and family members at the end of life, silence often becomes more prevalent. Silence is acknowledged as integral to interpersonal communication and compassionate care but is also noted as a complex and ambiguous phenomenon. This review seeks interdisciplinary experience to deepen understanding of qualities of silence as an element of care. To search for published papers which describe professional caregivers' experience of silence as an element of care, in palliative and other clinical, spiritual and pastoral care settings and to synthesise their findings. Meta-ethnography: employing a systematic search strategy and line-of-argument synthesis. PsycINFO and seven other cross-disciplinary databases, supplemented by hand-search, review of reference lists and citation tracking. No date range was imposed. Inclusion criteria focused on reported experience of silence in professional caregiving. Selected papers ( n = 18) were appraised; none were rejected on grounds of quality. International, interdisciplinary research and opinion endorses the value of silence in clinical care. As a multi-functional element of interpersonal relationships, silence operates in partnership with speech to support therapeutic communication. As a caregiving practice, silence is perceived as particularly relevant in spiritual and existential dimensions of care when words may fail. Experience of silence as an element of care was found in palliative and spiritual care, psychotherapy and counselling supporting existing recognition of the value of silence as a skill and practice. Because silence can present challenges for caregivers, greater understanding may offer benefits for clinical practice.

  12. Controlling low frequency noise using a passive silencer

    Energy Technology Data Exchange (ETDEWEB)

    DeGagne, D.C.; Faszer, A.C. [Noise Solutions Inc., Calgary, AB (Canada)

    2009-07-01

    Nearly 85 per cent of all the oil and natural gas recovered in Canada comes from Alberta where noise emissions from energy facilities are regulated by the Energy Resources Conservation Board (ERCB) and the Alberta Utilities Commission (AUC) through Noise Control Directive D-038. Operators of energy facilities in Alberta must meet the Permissible Sound Level (PSL) established for industrial facilities that are established for receptor locations such as nearby residences. Despite efforts to manage noise, complaints from nearby residents continue to occur even if the facility is in compliance. This is because high and mid frequency components can decay or be absorbed by air and ground conditions leaving mostly low frequency noise (LFN) at the residence. This paper explored the significance of LFN and how some facility operators are dealing with this problem. The impacts of LFN can range from creating a sensation of pressure in the ear, disturbing normal conversation, to creating secondary vibrating effects within homes. If severe enough, it can also result in potential behavioural dysfunction such as task performance deterioration, sleep disturbance and headaches. In 2006, Noise Solutions Inc. was approached by Hunt Oil Company regarding the installation of a new compressor at their Caroline site. The proposal posed a serious noise problem for the community which requested that the new compressor unit be developed without any additional noise impact on the area. Noise Solutions Inc. used a multi-phased approach to develop the most effective LFN silencer using best practical technology and materials. In an effort to fully attenuate both the high frequency noise (dBA) and the low frequency noise (dBC) of the new compressor unit, Noise Solutions and Hunt Oil agreed that a significant level of sound-suppression would be necessary. The entire noise-suppression unit was specially designed to compensate for the sheer size of the compressor building. The first step to

  13. Le silence, ce cri qui résonne dans l’écriture de Viviane Forrester

    Directory of Open Access Journals (Sweden)

    Amelia Peral Crespo

    2015-11-01

    Full Text Available The Holocaust Literature is tied to Silence from its beginning as the writing to silence. Write about the Holocaust and relate the experiences lived in first person or transmit them to the coming generations means leaving the silence which, for years, was the ideal refuge. This research focuses on the literary production of Viviane Forrester. The different expressions of silence that characterize her writings are analyzed. Silence is the cry that underlies in the most profound of the human being that return from the concentration camps, as Lazarus from the dead. It is a silence that grows to a cry because Forrester’s writing, almost in parallel to the fragmentary writing of Blanchot, an-nounces livre à venir, expressing the cry in silence without the ending of the word

  14. Preclinical Evaluation of a Lentiviral Vector for Huntingtin Silencing

    Directory of Open Access Journals (Sweden)

    Karine Cambon

    2017-06-01

    Full Text Available Huntington’s disease (HD is an autosomal dominant neurodegenerative disorder resulting from a polyglutamine expansion in the huntingtin (HTT protein. There is currently no cure for this disease, but recent studies suggest that RNAi to downregulate the expression of both normal and mutant HTT is a promising therapeutic approach. We previously developed a small hairpin RNA (shRNA, vectorized in an HIV-1-derived lentiviral vector (LV, that reduced pathology in an HD rodent model. Here, we modified this vector for preclinical development by using a tat-independent third-generation LV (pCCL backbone and removing the original reporter genes. We demonstrate that this novel vector efficiently downregulated HTT expression in vitro in striatal neurons derived from induced pluripotent stem cells (iPSCs of HD patients. It reduced two major pathological HD hallmarks while triggering a minimal inflammatory response, up to 6 weeks after injection, when administered by stereotaxic surgery in the striatum of an in vivo rodent HD model. Further assessment of this shRNA vector in vitro showed proper processing by the endogenous silencing machinery, and we analyzed gene expression changes to identify potential off-targets. These preclinical data suggest that this new shRNA vector fulfills primary biosafety and efficiency requirements for further development in the clinic as a cure for HD.

  15. Breaking the silence, dismantling taboos: Latino novels on AIDS.

    Science.gov (United States)

    Sandoval Sánchez, A

    1998-01-01

    As AIDS has ravaged the world in the last two decades, literature has played an important role in giving testimony of the epidemic. According to different communities and particular experiences, AIDS literature can offer ways of coping and surviving. In the last few years the U.S. Latino/a population has been highly affected by AIDS. The first genres to register AIDS were poetry and theatre. In this essay I examine how AIDS is represented in the first four Latino novels to deal with the subject matter: Ana Castillo's So Far from God, Daniel Torres's Morirás si da una primavera, Elías Miguel Muñoz's The Greatest Performance, and Jaime Manrique's latin Moon in Manhattan. My critical reading centers on how AIDS constitutes a new articulation of identity, particularly gay and ethnic identity. Most importantly, I propose that these novels contribute to dismantling homophobia and compulsory heterosexuality, deconstructing sexual and cultural taboos, and breaking the silence on AIDS/SIDA.

  16. Sox6 directly silences epsilon globin expression in definitive erythropoiesis.

    Directory of Open Access Journals (Sweden)

    2006-02-01

    Full Text Available Sox6 is a member of the Sox transcription factor family that is defined by the conserved high mobility group (HMG DNA binding domain, first described in the testis determining gene, Sry. Previous studies have suggested that Sox6 plays a role in the development of the central nervous system, cartilage, and muscle. In the Sox6-deficient mouse, p100H, epsilony globin is persistently expressed, and increased numbers of nucleated red cells are present in the fetal circulation. Transfection assays in GM979 (erythroleukemic cells define a 36-base pair region of the epsilony proximal promoter that is critical for Sox6 mediated repression. Electrophoretic mobility shift assay (EMSA and chromatin immunoprecipitation (ChIP assays demonstrate that Sox6 acts as a repressor by directly binding to the epsilony promoter. The normal expression of Sox6 in wild-type fetal liver and the ectopic expression of epsilony in p100H homozygous fetal liver demonstrate that Sox6 functions in definitive erythropoiesis. The present study shows that Sox6 is required for silencing of epsilony globin in definitive erythropoiesis and suggests a role for Sox6 in erythroid cell maturation. Thus, Sox6 regulation of epsilony globin might provide a novel therapeutical target in the treatment of hemoglobinopathies such as sickle cell anemia and thalassemia.

  17. Grandparents' experiences of childhood cancer, part 1: doubled and silenced.

    Science.gov (United States)

    Moules, Nancy J; Laing, Catherine M; McCaffrey, Graham; Tapp, Dianne M; Strother, Douglas

    2012-01-01

    In this study, the authors examined the experiences of grandparents who have had, or have, a grandchild with childhood cancer. Sixteen grandparents were interviewed using unstructured interviews, and the data were analyzed according to hermeneutic-phenomenological tradition, as guided by the philosophical hermeneutics of Hans-Georg Gadamer. Interpretive findings indicate that grandparents suffer and worry in many complex ways that include a doubled worry for their own children as well as their grandchildren. According to the grandparents in this study, this worry was, at times, silenced in efforts to protect the parents of the grandchild from the burden of concern for the grandparent. Other interpretations include the nature of having one's universe shaken, of having lives put on hold, and a sense of helplessness. The grandparents in this study offer advice to other grandparents as well as to the health care system regarding what kinds of things might have been more helpful to them as one level of the family system, who, like other subsystems of the family, are also profoundly affected by the event of childhood cancer.

  18. Nature to the natural rescue: Silencing microbial chats.

    Science.gov (United States)

    Paul, Diby; Gopal, Judy; Kumar, Manish; Manikandan, Muthu

    2018-01-25

    Communication is the sole means by which effective networking and co-existence is accomplished amongst living beings. Microbes have their own chit-chats. Science has overheard these microbial gossips and have concluded that these aren't just informal communications, but carefully coordinated signals that plan their effective strategies. Tracking one such signal molecule, N-acyl homoserine lactone (AHL), led to a fundamental understanding to microbial quorum sensing (QS). Furtherance of research sought for ways to cut off communication between these virulent forms, so as to hinder their combinatorial attacks through quorum sensing inhibitors (QSIs). A clear understanding of the inhibitors of these microbial communication systems is vital to destroy their networking and co-working. The current review, consolidates the solutions for QSIs offered from natural sources against these micro components, that are capable of slaughtering even nature's most fit entity-man. The applications of effective out sourcing of this QSI technologies and the need for development are discussed. The importance of silencing this microbial chatter to various aspects of human life and their implications are discussed and elaborated. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Silence in liturgy as the space for the Holy Ghost’s activity

    Directory of Open Access Journals (Sweden)

    Adelajda Sielepin

    2006-06-01

    Full Text Available The aim of this article is to clarify the essential and often neglected function of liturgical silence. In practice silence is usually intended to prepare the participants for listening or reflecting upon the word, especially when proclaimed by the minister. Whereas it is vital to know that silence constitutes a creative element of the liturgy, because the involvement of the Holy Spirit. In His action and cooperation with the participants He enables them to get into communion with Christ the Word and the Person and eventually to join effectively His mission. In that sense silence helps the Holy Ghost to fulfill His function in continuing the dialogue between God and man as well as in enhancing one’s spiritual skills for the fruitful participation in the Mystery of Christ and the Church.

  20. Reticence in Silence. An Examination of Heidegger's Phenomenology of Language in Contributions to Philosophy

    Czech Academy of Sciences Publication Activity Database

    Nitsche, Martin

    2011-01-01

    Roč. 765, č. 1 (2011), s. 74-79 ISSN 1407-2157 Institutional research plan: CEZ:AV0Z90090514 Keywords : Heidegger * contributions to philosophy * phenomenology * language * reticence in silence Subject RIV: AA - Philosophy ; Religion

  1. Viral suppressors of RNA silencing hinder exogenous and endogenous small RNA pathways in Drosophila.

    Directory of Open Access Journals (Sweden)

    Bassam Berry

    2009-06-01

    Full Text Available In plants and insects, RNA interference (RNAi is the main responder against viruses and shapes the basis of antiviral immunity. Viruses counter this defense by expressing viral suppressors of RNAi (VSRs. While VSRs in Drosophila melanogaster were shown to inhibit RNAi through different modes of action, whether they act on other silencing pathways remained unexplored.Here we show that expression of various plant and insect VSRs in transgenic flies does not perturb the Drosophila microRNA (miRNA pathway; but in contrast, inhibits antiviral RNAi and the RNA silencing response triggered by inverted repeat transcripts, and injection of dsRNA or siRNA. Strikingly, these VSRs also suppressed transposon silencing by endogenous siRNAs (endo-siRNAs.Our findings identify VSRs as tools to unravel small RNA pathways in insects and suggest a cosuppression of antiviral RNAi and endo-siRNA silencing by viruses during fly infections.

  2. A viral suppressor protein inhibits host RNA silencing by hooking up with Argonautes

    KAUST Repository

    Jin, Hailing

    2010-05-01

    RNA viruses are particularly vulnerable to RNAi-based defenses in the host, and thus have evolved specific proteins, known as viral suppressors of RNA silencing (VSRs), as a counterdefense. In this issue of Genes & Development, Azevedo and colleagues (pp. 904-915) discovered that P38, the VSR of Turnip crinkle virus, uses its glycine/tryptophane (GW) motifs as an ARGONAUTE (AGO) hook to attract and disarm the host\\'s essential effector of RNA silencing. Several GW motif-containing cellular proteins are known to be important partners of AGOs in RNA silencing effector complexes in yeast, plants, and animals. The GW motif appears to be a versatile and effective tool for regulating the activities of RNA silencing pathways, and the use of GW mimicry to compete for and inhibit host AGOs may be a strategy used by many pathogens to counteract host RNAi-based defenses. © 2010 by Cold Spring Harbor Laboratory Press.

  3. Identifying Silence Climate in Organizations in the Framework of Contemporary Management Approaches

    Directory of Open Access Journals (Sweden)

    Mustafa Emre Civelek

    2015-10-01

    Full Text Available Dynamic competition conditions in present day, bring about the consequence for businesses to face varied problems with each passing day. At this point, current management approaches include studies that would shed light on the new problems of businesses. Organizational Silence, a concept that has recently been being voiced in business world, has come up in such context. Organizational silence could be expressed as the employee behavior of keeping silent about certain negativities due to various reasons in an organization. Since knowledge sharing in modern organizations is of capital importance in terms of responding hastily to the changes in a competitive environment, spread of this behavior of employees to organization culture and climate presents a threat of indifference. In this study, the concept of Organizational Silence is defined and the effects of conceived silence climate on management of organizations are discussed.

  4. Identifying Silence Climate in Organizations in the Framework of Contemporary Management Approaches

    Directory of Open Access Journals (Sweden)

    Mustafa Emre Civelek

    2015-12-01

    Full Text Available Dynamic competition conditions in present day bring about the consequence for businesses to face varied problems with each passing day. At this point, current management approaches include studies that would shed light on the new problems of businesses. Organizational Silence, a concept that has recently been being voiced in business world, has come up in such context. Organizational silence could be expressed as the employee behavior of keeping silent about certain negativities due to various reasons in an organization. Since knowledge sharing in modern organizations is of capital importance in terms of responding hastily to the changes in a competitive environment, spread of this behavior of employees to organization culture and climate presents a threat of indifference. In this study, the concept of Organizational Silence is defined and the effects of conceived silence climate on management of organizations are discussed.

  5. Dissection of tomato lycopene biosynthesis through virus-induced gene silencing.

    Science.gov (United States)

    Fantini, Elio; Falcone, Giulia; Frusciante, Sarah; Giliberto, Leonardo; Giuliano, Giovanni

    2013-10-01

    Lycopene biosynthesis in tomato (Solanum lycopersicum) fruits has been proposed to proceed through a poly-cis pathway catalyzed by phytoene synthase (PSY), two desaturases (phytoene desaturase [PDS] and ζ-carotene desaturase [ZDS]), and two cis-trans isomerases (ζ-carotene isomerase [ZISO] and prolycopene isomerase [CrtISO]). The mechanism of action of these enzymes has been studied in Escherichia coli, but a systematic study of their in vivo function is lacking. We studied the function of nine candidate genes (PSY1, PSY2, PSY3, PDS, ZDS, ZISO, CrtISO, CrtISO-Like1, and CrtISO-Like2) using virus-induced gene silencing (VIGS) coupled to high-resolution liquid chromatography coupled with diode array detector and mass spectrometry, which allowed the identification and quantitation of 45 different carotenoid isomers, including linear xanthophylls. The data confirm the confinement of the VIGS signal to the silenced fruits and the similarity of the phenotypes of PSY1- and CrtISO-silenced fruits with those of the yellow flesh and tangerine mutants. Light was able to restore lycopene biosynthesis in ZISO-silenced fruits. Isomeric composition of fruits silenced at different metabolic steps suggested the existence of three functional units, comprising PSY1, PDS/ZISO, and ZDS/CrtISO, and responsible for the synthesis of 15-cis-phytoene, 9,9'-di-cis-ζ-carotene, and all-trans-lycopene, respectively. Silencing of a desaturase (PDS or ZDS) resulted in the induction of the isomerase in the same functional unit (ZISO or CrtISO, respectively). All-trans-ζ-carotene was detectable in nonsilenced fruits, greatly increased in ZDS-silenced ones, and disappeared in CrtISO-Like1-/CrtISO-Like2-silenced ones, suggesting the existence of a metabolic side branch, comprising this compound and initiated by the latter enzymes.

  6. 'Checkmating HIV&AIDS': Using chess to break the silence in the ...

    African Journals Online (AJOL)

    Omar Esau

    2012-12-13

    Dec 13, 2012 ... Keywords: HIV&AIDS, action research, chess, checkmating, culture of silence, prevention, awareness. Résumé. Cet article est un compte rendu de mon projet de recherche-action « mettre le VIH/SIDA échec et mat », qui avait pour but de briser dans ma classe la « culture du silence » au sujet du VIH/SIDA ...

  7. Silencing of the rotavirus NSP4 protein decreases the incidence of biliary atresia in murine model.

    Directory of Open Access Journals (Sweden)

    Jiexiong Feng

    Full Text Available Biliary atresia is a common disease in neonates which causes obstructive jaundice and progressive hepatic fibrosis. Our previous studies indicate that rotavirus infection is an initiator in the pathogenesis of experimental biliary atresia (BA through the induction of increased nuclear factor-kappaB and abnormal activation of the osteopontin inflammation pathway. In the setting of rotavirus infection, rotavirus nonstructural protein 4 (NSP4 serves as an important immunogen, viral protein 7 (VP7 is necessary in rotavirus maturity and viral protein 4 (VP4 is a virulence determiner. The purpose of the current study is to clarify the roles of NSP4, VP7 and VP4 in the pathogenesis of experimental BA. Primary cultured extrahepatic biliary epithelia were infected with Rotavirus (mmu18006. Small interfering RNA targeting NSP4, VP7 or VP4 was transfected before rotavirus infection both in vitro and in vivo. We analyzed the incidence of BA, morphological change, morphogenesis of viral particles and viral mRNA and protein expression. The in vitro experiments showed NSP4 silencing decreased the levels of VP7 and VP4, reduced viral particles and decreased cytopathic effect. NSP4-positive cells had strongly positive expression of integrin subunit α2. Silencing of VP7 or VP4 partially decreased epithelial injury. Animal experiments indicated after NSP4 silencing, mouse pups had lower incidence of BA than after VP7 or VP4 silencing. However, 33.3% of VP4-silenced pups (N = 6 suffered BA and 50% of pups (N = 6 suffered biliary injury after VP7 silencing. Hepatic injury was decreased after NSP4 or VP4 silencing. Neither VP4 nor VP7 were detected in the biliary ducts after NSP4. All together, NSP4 silencing down-regulates VP7 and VP4, resulting in decreased incidence of BA.

  8. Supervised learning classification models for prediction of plant virus encoded RNA silencing suppressors.

    Directory of Open Access Journals (Sweden)

    Zeenia Jagga

    Full Text Available Viral encoded RNA silencing suppressor proteins interfere with the host RNA silencing machinery, facilitating viral infection by evading host immunity. In plant hosts, the viral proteins have several basic science implications and biotechnology applications. However in silico identification of these proteins is limited by their high sequence diversity. In this study we developed supervised learning based classification models for plant viral RNA silencing suppressor proteins in plant viruses. We developed four classifiers based on supervised learning algorithms: J48, Random Forest, LibSVM and Naïve Bayes algorithms, with enriched model learning by correlation based feature selection. Structural and physicochemical features calculated for experimentally verified primary protein sequences were used to train the classifiers. The training features include amino acid composition; auto correlation coefficients; composition, transition, and distribution of various physicochemical properties; and pseudo amino acid composition. Performance analysis of predictive models based on 10 fold cross-validation and independent data testing revealed that the Random Forest based model was the best and achieved 86.11% overall accuracy and 86.22% balanced accuracy with a remarkably high area under the Receivers Operating Characteristic curve of 0.95 to predict viral RNA silencing suppressor proteins. The prediction models for plant viral RNA silencing suppressors can potentially aid identification of novel viral RNA silencing suppressors, which will provide valuable insights into the mechanism of RNA silencing and could be further explored as potential targets for designing novel antiviral therapeutics. Also, the key subset of identified optimal features may help in determining compositional patterns in the viral proteins which are important determinants for RNA silencing suppressor activities. The best prediction model developed in the study is available as a

  9. Synthetic RNA Silencing in Bacteria – Antimicrobial Discovery and Resistance Breaking

    OpenAIRE

    Good, Liam; Stach, James E. M.

    2011-01-01

    The increasing incidence and prevalence of antibiotic resistance in bacteria threatens the “antibiotic miracle.” Conventional antimicrobial drug development has failed to replace the armamentarium needed to combat this problem, and novel solutions are urgently required. Here we review both natural and synthetic RNA silencing and its potential to provide new antibacterials through improved target selection, evaluation, and screening. Furthermore, we focus on synthetic RNA silencers as a novel ...

  10. Organizational Silence, from Roots to Solutions: A Case Study in Iran Petroleum Industry

    Directory of Open Access Journals (Sweden)

    Mehdi Afkhami Ardakani

    2015-05-01

    Full Text Available Organizational silence is defined as the lack of effective interactions among staff and it stands opposite to the concept of organizational voice. In the present research, the purpose is to measure the silence behavior among the Research Institute of Petroleum Industry (RIPI staff before and after the implementation of a comprehensive suggestion system. A suggestion system is an internal structure easily accessed by all the staff to state their suggestions in a pre-structured format. The roots of silence behavior are studied based on a deep literature review to find out possible solutions to improve organizational voice. To conduct the research, a self-structured questionnaire has been developed and distributed among all the staff. A quasi-experimental methodology has been adopted to compare pretest and post-test results of silence status before and after implementing the suggestion system. The results show that the silence behavior has been meaningfully reduced. This is based on a simple t-test performed by SPSS software, where there is a meaningful difference between the silence status of pre-test and post-test. In other words, a suggestion system could be a communication opportunity to encourage staff to provide suggestions and to cooperate for promoting the organization, which will finally reduce the organization silence. A major gap within the studies of Iranian scholars about organizational silence is the failure to introduce effective solutions to reduce it. However, this research is innovative in the sense that it fills the mentioned gap. This research shows that large scale organizations like RIPI need to consider methods like suggestion systems to break bureaucratic obstacles so that their staff can easily find open routes to share their ideas and suggestions in a prestructured format. This cooperating will lead to mutual benefits for both parts, since suggestions could be used to enhance organizational structure and performance and

  11. Virus-Induced Gene Silencing as a Tool to Study Tomato Fruit Biochemistry.

    Science.gov (United States)

    Fantini, Elio; Giuliano, Giovanni

    2016-01-01

    Virus-Induced Gene Silencing (VIGS) is an excellent reverse genetic tool for the study of gene function in plants, based on virus infection. In this chapter, we describe a high-throughput approach based on VIGS for the study of tomato fruit biochemistry. It comprises the selection of the sequence for silencing using bioinformatics tools, the cloning of the fragment in the Tobacco Rattle Virus (TRV), and the agroinfiltration of tomato fruits mediated by Agrobacterium tumefaciens.

  12. Virus-induced gene silencing and Agrobacterium tumefaciens-mediated transient expression in Nicotiana tabacum.

    Science.gov (United States)

    Zhang, Zhao; Thomma, Bart P H J

    2014-01-01

    Virus-induced gene silencing (VIGS) is a rapid method for transient silencing of plant genes. In this chapter, we describe the methodology for Tobacco rattle virus (TRV)-based VIGS in Nicotiana tabacum. In combination with subsequent co-expression of the tomato immune receptor Ve1 and the corresponding Verticillium effector Ave1 through Agrobacterium tumefaciens-mediated transient transformation (agroinfiltration), we established a rapid system for assessing the requirement of candidate plant genes for Ve1-mediated immune signaling.

  13. The molecular basis for stability of heterochromatin-mediated silencing in mammals

    Directory of Open Access Journals (Sweden)

    Hiragami-Hamada Kyoko

    2009-11-01

    Full Text Available Abstract The archetypal epigenetic phenomenon of position effect variegation (PEV in Drosophila occurs when a gene is brought abnormally close to heterochromatin, resulting in stochastic silencing of the affected gene in a proportion of cells that would normally express it. PEV has been instrumental in unraveling epigenetic mechanisms. Using an in vivo mammalian model for PEV we have extensively investigated the molecular basis for heterochromatin-mediated gene silencing. Here we distinguish 'epigenetic effects' from other cellular differences by studying ex vivo cells that are identical, apart from the expression of the variegating gene which is silenced in a proportion of the cells. By separating cells according to transgene expression we show here that silencing appears to be associated with histone H3 lysine 9 trimethylation (H3K9me3, DNA methylation and the localization of the silenced gene to a specific nuclear compartment enriched in these modifications. In contrast, histone H3 acetylation (H3Ac and lysine 4 di or tri methylation (H3K4me2/3 are the predominant modifications associated with expression where we see the gene in a euchromatic compartment. Interestingly, DNA methylation and inaccessibility, rather than H3K9me3, correlated most strongly with resistance to de-repression by cellular activation. These results have important implications for understanding the contribution of specific factors involved in the establishment and maintenance of gene silencing and activation in vivo.

  14. The Nuclear Cap-Binding Complex Mediates Meiotic Silencing by Unpaired DNA

    Directory of Open Access Journals (Sweden)

    Logan M. Decker

    2017-04-01

    Full Text Available In the filamentous fungus Neurospora crassa, cross walls between individual cells are normally incomplete, making the entire fungal network vulnerable to attack by viruses and selfish DNAs. Accordingly, several genome surveillance mechanisms are maintained to help the fungus combat these repetitive elements. One of these defense mechanisms is called meiotic silencing by unpaired DNA (MSUD, which identifies and silences unpaired genes during meiosis. Utilizing common RNA interference (RNAi proteins, such as Dicer and Argonaute, MSUD targets mRNAs homologous to the unpaired sequence to achieve silencing. In this study, we have identified an additional silencing component, namely the cap-binding complex (CBC. Made up of cap-binding proteins CBP20 and CBP80, CBC associates with the 5′ cap of mRNA transcripts in eukaryotes. The loss of CBC leads to a deficiency in MSUD activity, suggesting its role in mediating silencing. As confirmed in this study, CBC is predominantly nuclear, although it is known to travel in and out of the nucleus to facilitate RNA transport. As seen in animals but not in plants, CBP20’s robust nuclear import depends on CBP80 in Neurospora. CBC interacts with a component (Argonaute of the perinuclear meiotic silencing complex (MSC, directly linking the two cellular factors.

  15. Strategy of gene silencing in cassava for validation of resistance genes

    International Nuclear Information System (INIS)

    Cortes, Simon; Lopez, Camilo

    2010-01-01

    Cassava (Manihot esculenta) is a major source of food for more than 1000 million people in the world and constitutes an important staple crop. Cassava bacterial blight, caused by the gram negative bacterium Xanthomonas axonopodis pv. manihotis, is one of the most important constraints for this crop. A candidate resistance gene against cassava bacterial blight, named RXam1, has been identified previously. In this work, we employed the gene silencing approach using the African cassava mosaic virus (ACMV) to validate the function of the RXam1 gene. We used as positive control the su gen, which produce photo blanching in leaves when is silenced. Plants from the SG10735 variety were bombardment with the ACMV-A-SU+ACMV-B y ACMV-A-RXam1+ACMV-B constructions. The silencing efficiency employing the su gene was low, only one of seven plants showed photo blanching. In the putative silenced plants for the RXam1 gene, no presence of siRNAs corresponding to RXam1 was observed; although a low diminution of the RXam1 gene expression was obtained. The growth curves for the Xam strain CIO136 in cassava plants inoculated showing a little but no significance difference in the susceptibility in the silenced plants compared to not silenced

  16. Silencing of the FRO1 gene and its effects on iron partition in Nicotiana benthamiana.

    Science.gov (United States)

    Gama, Florinda; Saavedra, Teresa; Dandlen, Susana; de Varennes, Amarilis; Correia, Pedro J; Pestana, Maribela; Nolasco, Gustavo

    2017-05-01

    To evaluate the dynamic role of the ferric-chelate reductase enzyme (FCR) and to identify possible pathways of regulation of its activity in different plant organs an investigation was conducted by virus-induced gene silencing (VIGS) using tobacco rattle virus (TRV) to silence the ferric reductase oxidase gene (FRO1) that encodes the FCR enzyme. Half of Nicotiana benthamiana plants received the VIGS vector and the rest remained as control. Four treatments were imposed: two levels of Fe in the nutrient solution (0 or 2.5 μM of Fe), each one with silenced or non-silenced (VIGS-0; VIGS-2.5) plants. Plants grown without iron (0; VIGS-0) developed typical symptoms of iron deficiency in the youngest leaves. To prove that FRO1 silencing had occurred, resupply of Fe (R) was done by adding 2.5 μM of Fe to the nutrient solution in a subset of chlorotic plants (0-R; VIGS-R). Twelve days after resupply, 0-R plants had recovered from Fe deficiency while plants containing the VIGS vector (VIGS-R) remained chlorotic and both FRO1 gene expression and FCR activity were considerably reduced, consequently preventing Fe uptake. With the VIGS technique we were able to silence the FRO1 gene in N. benthamiana and point out its importance in chlorophyll synthesis and Fe partition. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  17. On the role of RNA silencing in the pathogenicity and evolution of viroids and viral satellites

    Science.gov (United States)

    Wang, Ming-Bo; Bian, Xue-Yu; Wu, Li-Min; Liu, Li-Xia; Smith, Neil A.; Isenegger, Daniel; Wu, Rong-Mei; Masuta, Chikara; Vance, Vicki B.; Watson, John M.; Rezaian, Ali; Dennis, Elizabeth S.; Waterhouse, Peter M.

    2004-01-01

    Viroids and most viral satellites have small, noncoding, and highly structured RNA genomes. How they cause disease symptoms without encoding proteins and why they have characteristic secondary structures are two longstanding questions. Recent studies have shown that both viroids and satellites are capable of inducing RNA silencing, suggesting a possible role of this mechanism in the pathology and evolution of these subviral RNAs. Here we show that preventing RNA silencing in tobacco, using a silencing suppressor, greatly reduces the symptoms caused by the Y satellite of cucumber mosaic virus. Furthermore, tomato plants expressing hairpin RNA, derived from potato spindle tuber viroid, developed symptoms similar to those of potato spindle tuber viroid infection. These results provide evidence suggesting that viroids and satellites cause disease symptoms by directing RNA silencing against physiologically important host genes. We also show that viroid and satellite RNAs are significantly resistant to RNA silencing-mediated degradation, suggesting that RNA silencing is an important selection pressure shaping the evolution of the secondary structures of these pathogens. PMID:14978267

  18. Feline immunodeficiency virus envelope glycoproteins antagonize tetherin through a distinctive mechanism that requires virion incorporation.

    Science.gov (United States)

    Morrison, James H; Guevara, Rebekah B; Marcano, Adriana C; Saenz, Dyana T; Fadel, Hind J; Rogstad, Daniel K; Poeschla, Eric M

    2014-03-01

    BST2/tetherin inhibits the release of enveloped viruses from cells. Primate lentiviruses have evolved specific antagonists (Vpu, Nef, and Env). Here we characterized tetherin proteins of species representing both branches of the order Carnivora. Comparison of tiger and cat (Feliformia) to dog and ferret (Caniformia) genes demonstrated that the tiger and cat share a start codon mutation that truncated most of the tetherin cytoplasmic tail early in the Feliformia lineage (19 of 27 amino acids, including the dual tyrosine motif). Alpha interferon (IFN-α) induced tetherin and blocked feline immunodeficiency virus (FIV) replication in lymphoid and nonlymphoid feline cells. Budding of bald FIV and HIV particles was blocked by carnivore tetherins. However, infectious FIV particles were resistant, and spreading FIV replication was uninhibited. Antagonism mapped to the envelope glycoprotein (Env), which rescued FIV from carnivore tetherin restriction when expressed in trans but, in contrast to known antagonists, did not rescue noncognate particles. Also unlike the primate lentiviral antagonists, but similar to the Ebola virus glycoprotein, FIV Env did not reduce intracellular or cell surface tetherin levels. Furthermore, FIV-enveloped FIV particles actually required tetherin for optimal release from cells. The results show that FIV Envs mediate a distinctive tetherin evasion. Well adapted to a phylogenetically ancient tetherin tail truncation in the Felidae, it requires functional virion incorporation of Env, and it shields the budding particle without downregulating plasma membrane tetherin. Moreover, FIV has evolved dependence on this protein: particles containing FIV Env need tetherin for optimal release from the cell, while Env(-) particles do not. HIV-1 antagonizes the restriction factor tetherin with the accessory protein Vpu, while HIV-2 and the filovirus Ebola use their envelope (Env) glycoproteins for this purpose. It turns out that the FIV tetherin antagonist is

  19. Antagonism of BST-2/Tetherin Is a Conserved Function of the Env Glycoprotein of Primary HIV-2 Isolates.

    Science.gov (United States)

    Chen, Chia-Yen; Shingai, Masashi; Welbourn, Sarah; Martin, Malcolm A; Borrego, Pedro; Taveira, Nuno; Strebel, Klaus

    2016-12-15

    Although HIV-2 does not encode a vpu gene, the ability to antagonize bone marrow stromal antigen 2 (BST-2) is conserved in some HIV-2 isolates, where it is controlled by the Env glycoprotein. We previously reported that a single-amino-acid difference between the laboratory-adapted ROD10 and ROD14 Envs controlled the enhancement of virus release (referred to here as Vpu-like) activity. Here, we investigated how conserved the Vpu-like activity is in primary HIV-2 isolates. We found that half of the 34 tested primary HIV-2 Env isolates obtained from 7 different patients enhanced virus release. Interestingly, most HIV-2 patients harbored a mixed population of viruses containing or lacking Vpu-like activity. Vpu-like activity and Envelope functionality varied significantly among Env isolates; however, there was no direct correlation between these two functions, suggesting they evolved independently. In comparing the Env sequences from one HIV-2 patient, we found that similar to the ROD10/ROD14 Envs, a single-amino-acid change (T568I) in the ectodomain of the TM subunit was sufficient to confer Vpu-like activity to an inactive Env variant. Surprisingly, however, absence of Vpu-like activity was not correlated with absence of BST-2 interaction. Taken together, our data suggest that maintaining the ability to antagonize BST-2 is of functional relevance not only to HIV-1 but also to HIV-2 as well. Our data show that as with Vpu, binding of HIV-2 Env to BST-2 is important but not sufficient for antagonism. Finally, as observed previously, the Vpu-like activity in HIV-2 Env can be controlled by single-residue changes in the TM subunit. Lentiviruses such as HIV-1 and HIV-2 encode accessory proteins whose function is to overcome host restriction mechanisms. Vpu is a well-studied HIV-1 accessory protein that enhances virus release by antagonizing the host restriction factor BST-2. HIV-2 does not encode a vpu gene. Instead, the HIV-2 Env glycoprotein was found to antagonize BST-2

  20. Antagonism of the prostaglandin D2 receptor CRTH2 attenuates asthma pathology in mouse eosinophilic airway inflammation

    DEFF Research Database (Denmark)

    Uller, Lena; Mathiesen, Jesper Mosolff; Alenmyr, Lisa

    2007-01-01

    , mast cells, and eosinophils to inflammatory sites, and has recently attracted interest as target for treatment of allergic airway diseases. The present study involving mice explores the specificity of CRTH2 antagonism of TM30089, which is structurally closely related to the dual TP/CRTH2 antagonist...... receptors including the related anaphylatoxin C3a and C5a receptors, selected chemokine receptors and the cyclooxygenase isoforms 1 and 2 which are all recognized players in allergic diseases. Furthermore, TM30089 and ramatroban, the latter used as a reference herein, similarly inhibited asthma pathology...... in vivo by reducing peribronchial eosinophilia and mucus cell hyperplasia. CONCLUSION: This is the first report to demonstrate anti-allergic efficacy in vivo of a highly selective small molecule CRTH2 antagonist. Our data suggest that CRTH2 antagonism alone is effective in mouse allergic airway...

  1. Silencing Huntington's chorea: Is RNA Interference a Potential Cure?

    Directory of Open Access Journals (Sweden)

    Gerlinde A. Metz

    2006-01-01

    Full Text Available In 1872, George Huntington described Huntington's disease as characterized by motor, cognitive and psychiatric impairments. Huntington's disease is a dominant and autosomal mutation on chromosome 4 featuring the insertion of numerous CAG repeats. CAG codes for the amino acid, glutmanine that forms part of the Huntingtin protein (htt. Excess glutamine attachments make htt prone to accumulate in neurons. Three genes can be considered when developing therapies for Huntington's disease. They include targeting the symptoms of the disease, the progression of the disease and the cause of the disease. By using RNA interference (RNAi, the cause of the disease can be targeted. RNAi is a method that could potentially silence the formation of abnormal htt. This paper will discuss how RNAi could potentially cure Huntington's disease, by describing the genetic and proteinomic basis of Huntington's disease, the function of RNAi in Huntington's disease and the problems of benefits of RNAi. Preliminary work using RNAi in transgenic mice has shown a decrease in the behavioural expression of the mutant Huntington gene. There are several limitations associated with using RNAi as a gene therapy. For example, the effects of RNAi are short lived. A transposition system such as Sleeping Beauty can be used to increase the integration of the gene, however, for patients who currently have Huntington's disease, RNAi may potentially be used in combination with drugs or other treatments to target both symptoms and the underlying cause of Huntington's disease. This combination could eventually alleviate many painful symptoms associated with Huntington's disease and could even stop the progressive neurodegeneration of Huntington's disease. This review concludes that a substantial amount of new research is still necessary before RNAi is directly applicable to human patients with Huntington's disease.

  2. Silencing by H-NS potentiated the evolution of Salmonella.

    Directory of Open Access Journals (Sweden)

    Sabrina S Ali

    2014-11-01

    Full Text Available The bacterial H-NS protein silences expression from sequences with higher AT-content than the host genome and is believed to buffer the fitness consequences associated with foreign gene acquisition. Loss of H-NS results in severe growth defects in Salmonella, but the underlying reasons were unclear. An experimental evolution approach was employed to determine which secondary mutations could compensate for the loss of H-NS in Salmonella. Six independently derived S. Typhimurium hns mutant strains were serially passaged for 300 generations prior to whole genome sequencing. Growth rates of all lineages dramatically improved during the course of the experiment. Each of the hns mutant lineages acquired missense mutations in the gene encoding the H-NS paralog StpA encoding a poorly understood H-NS paralog, while 5 of the mutant lineages acquired deletions in the genes encoding the Salmonella Pathogenicity Island-1 (SPI-1 Type 3 secretion system critical to invoke inflammation. We further demonstrate that SPI-1 misregulation is a primary contributor to the decreased fitness in Salmonella hns mutants. Three of the lineages acquired additional loss of function mutations in the PhoPQ virulence regulatory system. Similarly passaged wild type Salmonella lineages did not acquire these mutations. The stpA missense mutations arose in the oligomerization domain and generated proteins that could compensate for the loss of H-NS to varying degrees. StpA variants most able to functionally substitute for H-NS displayed altered DNA binding and oligomerization properties that resembled those of H-NS. These findings indicate that H-NS was central to the evolution of the Salmonellae by buffering the negative fitness consequences caused by the secretion system that is the defining characteristic of the species.

  3. Virus-induced gene silencing (VIGS) in Nicotiana benthamiana and tomato.

    Science.gov (United States)

    Velásquez, André C; Chakravarthy, Suma; Martin, Gregory B

    2009-06-10

    RNA interference (RNAi) is a highly specific gene-silencing phenomenon triggered by dsRNA. This silencing mechanism uses two major classes of RNA regulators: microRNAs, which are produced from non-protein coding genes and short interfering RNAs (siRNAs). Plants use RNAi to control transposons and to exert tight control over developmental processes such as flower organ formation and leaf development. Plants also use RNAi to defend themselves against infection by viruses. Consequently, many viruses have evolved suppressors of gene silencing to allow their successful colonization of their host. Virus-induced gene silencing (VIGS) is a method that takes advantage of the plant RNAi-mediated antiviral defense mechanism. In plants infected with unmodified viruses the mechanism is specifically targeted against the viral genome. However, with virus vectors carrying sequences derived from host genes, the process can be additionally targeted against the corresponding host mRNAs. VIGS has been adapted for high-throughput functional genomics in plants by using the plant pathogen Agrobacterium tumefaciens to deliver, via its Ti plasmid, a recombinant virus carrying the entire or part of the gene sequence targeted for silencing. Systemic virus spread and the endogenous plant RNAi machinery take care of the rest. dsRNAs corresponding to the target gene are produced and then cleaved by the ribonuclease Dicer into siRNAs of 21 to 24 nucleotides in length. These siRNAs ultimately guide the RNA-induced silencing complex (RISC) to degrade the target transcript. Different vectors have been employed in VIGS and one of the most frequently used is based on tobacco rattle virus (TRV). TRV is a bipartite virus and, as such, two different A. tumefaciens strains are used for VIGS. One carries pTRV1, which encodes the replication and movement viral functions while the other, pTRV2, harbors the coat protein and the sequence used for VIGS. Inoculation of Nicotiana benthamiana and tomato seedlings

  4. IPI-145 antagonizes intrinsic and extrinsic survival signals in chronic lymphocytic leukemia cells.

    Science.gov (United States)

    Dong, Shuai; Guinn, Daphne; Dubovsky, Jason A; Zhong, Yiming; Lehman, Amy; Kutok, Jeffery; Woyach, Jennifer A; Byrd, John C; Johnson, Amy J

    2014-12-04

    Chronic lymphocytic leukemia (CLL) displays constitutive phosphatidylinositol 3-kinase (PI3K) activation resulting from aberrant regulation of B-cell receptor (BCR) signaling. Previous studies have shown that an oral PI3K p110δ inhibitor idelalisib exhibits promising activity in CLL. Here, we demonstrate that a dual PI3K p110δ and p110γ inhibitor, IPI-145, antagonizes BCR crosslinking activated prosurvival signals in primary CLL cells. IPI-145 causes direct killing in primary CLL cells in a dose- and time-dependent fashion, but does not generate direct cytotoxicity to normal B cells. However, IPI-145 does reduce the viability of normal T and natural killer cells and decrease activated T-cell production of various inflammatory and antiapoptotic cytokines. Furthermore, IPI-145 overcomes the ibrutinib resistance resulting from treatment-induced BTK C481S mutation. Collectively, these studies provide rationale for ongoing clinical evaluation of IPI-145 as a targeted therapy for CLL and related B-cell lymphoproliferative disorders. © 2014 by The American Society of Hematology.

  5. Selective histamine H1 antagonism: novel hypnotic and pharmacologic actions challenge classical notions of antihistamines.

    Science.gov (United States)

    Stahl, Stephen M

    2008-12-01

    Numerous "antihistamines" as well as various psychotropic medications with antihistamine properties are widely utilized to treat insomnia. Over-the-counter sleep aids usually contain an antihistamine and various antidepressants and antipsychotics with antihistamine properties have sedative-hypnotic actions. Although widely used for the treatment of insomnia, many agents that block the histamine H1 receptor are also widely considered to have therapeutic limitations, including the development of next-day carryover sedation, as well as problems with chronic use, such as the development of tolerance to sedative-hypnotic actions and weight gain. Although these clinical actions are classically attributed to blockade of the H1 receptor, recent findings with H1 selective agents and H1 selective dosing of older agents are challenging these notions and suggest that some of the clinical limitations of current H1-blocking agents at their currently utilized doses could be attributable to other properties of these drugs, especially to their simultaneous actions on muscarinic, cholinergic, and adrenergic receptors. Selective H1 antagonism is emerging as a novel approach to the treatment of insomnia, without tolerance, weight gain, or the need for the restrictive prescription scheduling required of other hypnotics.

  6. ANTAGONISM OF PROGESTERONE RECEPTOR SUPPRESSES CAROTID BODY RESPONSES TO HYPOXIA AND NICOTINE IN RAT PUPS

    Science.gov (United States)

    JOSEPH, V.; NIANE, L. M.; BAIRAM, A.

    2013-01-01

    We tested the hypothesis that antagonism of progesterone receptor (PR) in newborn rats alters carotid body and respiratory responses to hypoxia and nicotinic receptor agonists. Rats were treated with the PR antagonist mifepristone (daily oral gavage 40 μg/g/d) or vehicle between post-natal days 3 and 15. In 11–14-day-old rats, we used in vitro carotid body/carotid sinus nerve preparation and whole body plethysmography to assess the carotid body and ventilatory responses to hypoxia (65 mmHg in vitro, 10% O2 in vivo) and to nicotinic receptor agonists (as an excitatory modulator of carotid body activity—nicotine 100 μM for in vitro studies, and epibatidine 5 μg/kg, i.p., which mainly acts on peripheral nicotinic receptors, for in vivo studies). The carotid body responses to hypoxia and nicotine were drastically reduced by mifepristone. Compared with vehicle, mifepristone-treated rats had a reduced body weight. The ventilatory response to epibatidine was attenuated; however, the hypoxic ventilatory response was similar between vehicle and mifepristone-treated pups. Immunohistochemical staining revealed that mifepristone treatment did not change carotid body morphology. We conclude that PR activity is a critical factor ensuring proper carotid body function in newborn rats. PMID:22326965

  7. Conditions that Stabilize Membrane Domains Also Antagonize n-Alcohol Anesthesia

    Science.gov (United States)

    Machta, Benjamin B.; Gray, Ellyn; Nouri, Mariam; McCarthy, Nicola L. C.; Gray, Erin M.; Miller, Ann L.; Brooks, Nicholas J.; Veatch, Sarah L.

    2016-08-01

    Diverse molecules induce general anesthesia with potency strongly correlated both with their hydrophobicity and their effects on certain ion channels. We recently observed that several n-alcohol anesthetics inhibit heterogeneity in plasma membrane derived vesicles by lowering the critical temperature ($T_c$) for phase separation. Here we exploit conditions that stabilize membrane heterogeneity to further test the correlation between the anesthetic potency of n-alcohols and effects on $T_c$. First we show that hexadecanol acts oppositely to n-alcohol anesthetics on membrane mixing and antagonizes ethanol induced anesthesia in a tadpole behavioral assay. Second, we show that two previously described `intoxication reversers' raise $T_c$ and counter ethanol's effects in vesicles, mimicking the findings of previous electrophysiological and behavioral measurements. Third, we find that hydrostatic pressure, long known to reverse anesthesia, also raises $T_c$ in vesicles with a magnitude that counters the effect of butanol at relevant concentrations and pressures. Taken together, these results demonstrate that $\\Delta T_c$ predicts anesthetic potency for n-alcohols better than hydrophobicity in a range of contexts, supporting a mechanistic role for membrane heterogeneity in general anesthesia.

  8. Passion flower extract antagonizes the expression of nicotine locomotor sensitization in rats.

    Science.gov (United States)

    Breivogel, Chris; Jamerson, Brenda

    2012-10-01

    Nicotine, a bioactive component of tobacco, is highly addictive. Numerous therapies have been developed or are currently under investigation for smoking cessation, and all have met with limited success and/or side effects, indicating the need for additional therapies. This study examines the ability of a commerically-available aqueous extract of Passiflora incarnata Linn. (Passifloraceae) to ameliorate the signs of nicotine sensitization using a rat model. Rats were administered 0.4 mg/kg nicotine or vehicle once a day for four consecutive days. Nicotine adminstration produces sensitization of locomotor activity, a phenomenon implicated in the development of nicotine dependence. On the fifth day, locomotor activity of the subjects was monitored as rats from each treatment group were administered 800 mg/kg of Passiflora incarnata extract (or its vehicle) followed by a challenge dose of 0.4 mg/kg nicotine. When given to rats sensitized to nicotine for 4 days, the challenge dose of nicotine increased locomotor activity by more than 2-fold over activity following nicotine challenge in rats treated with vehicle during the sensitization phase. The difference was significant from 15-40 min after nicotine administration. Rats sensitized to nicotine then treated with Passiflora incarnata extract prior to the nicotine challenge exhibited a level of locomotor activity the same as the vehicle-treated controls. Passiflora incarnata extract did antagonize the expression of nicotine locomotor sensitization. Passiflora incarnata extract should be examined in future studies to evaluate its potential for treating nicotine addiction in humans.

  9. Biological activity of the non-microbial fraction of kefir: antagonism against intestinal pathogens.

    Science.gov (United States)

    Iraporda, Carolina; Abatemarco Júnior, Mário; Neumann, Elisabeth; Nunes, Álvaro Cantini; Nicoli, Jacques R; Abraham, Analía G; Garrote, Graciela L

    2017-08-01

    Kefir is a fermented milk obtained by the activity of kefir grains which are composed of lactic and acetic acid bacteria, and yeasts. Many beneficial health effects have been associated with kefir consumption such as stimulation of the immune system and inhibition of pathogenic microorganisms. The biological activity of kefir may be attributed to the presence of a complex microbiota as well as the microbial metabolites that are released during fermentation. The aim of this work was to characterise the non-microbial fraction of kefir and to study its antagonism against Escherichia coli, Salmonella spp. and Bacillus cereus. During milk fermentation there was a production of organic acids, mainly lactic and acetic acid, with a consequent decrease in pH and lactose content. The non-microbial fraction of kefir added to nutrient broth at concentrations above 75% v/v induced a complete inhibition of pathogenic growth that could be ascribed to the presence of un-dissociated lactic acid. In vitro assays using an intestinal epithelial cell model indicated that pre-incubation of cells with the non-microbial fraction of kefir did not modify the association/invasion of Salmonella whereas pre-incubation of Salmonella with this fraction under conditions that did not affect their viability significantly decreased the pathogen's ability to invade epithelial cells. Lactate exerted a protective effect against Salmonella in a mouse model, demonstrating the relevance of metabolites present in the non-microbial fraction of kefir produced during milk fermentation.

  10. ToxR Antagonizes H-NS Regulation of Horizontally Acquired Genes to Drive Host Colonization.

    Directory of Open Access Journals (Sweden)

    Misha I Kazi

    2016-04-01

    Full Text Available The virulence regulator ToxR initiates and coordinates gene expression needed by Vibrio cholerae to colonize the small intestine and cause disease. Despite its prominence in V. cholerae virulence, our understanding of the direct ToxR regulon is limited to four genes: toxT, ompT, ompU and ctxA. Here, we determine ToxR's genome-wide DNA-binding profile and demonstrate that ToxR is a global regulator of both progenitor genome-encoded genes and horizontally acquired islands that encode V. cholerae's major virulence factors and define pandemic lineages. We show that ToxR shares more than a third of its regulon with the histone-like nucleoid structuring protein H-NS, and antagonizes H-NS binding at shared binding locations. Importantly, we demonstrate that this regulatory interaction is the critical function of ToxR in V. cholerae colonization and biofilm formation. In the absence of H-NS, ToxR is no longer required for V. cholerae to colonize the infant mouse intestine or for robust biofilm formation. We further illustrate a dramatic difference in regulatory scope between ToxR and other prominent virulence regulators, despite similar predicted requirements for DNA binding. Our results suggest that factors in addition to primary DNA structure influence the ability of ToxR to recognize its target promoters.

  11. Structural insight into antibody-mediated antagonism of the Glucagon-like peptide-1 Receptor

    DEFF Research Database (Denmark)

    Hennen, Stephanie; Kodra, János T; Soroka, Vladyslav

    2016-01-01

    The Glucagon-like peptide-1 receptor (GLP-1R) is a member of the class B G protein-coupled receptor (GPCR) family and a well-established target for the treatment of type 2 diabetes. The N-terminal extracellular domain (ECD) of GLP-1R is important for GLP-1 binding and the crystal structure...... of the GLP-1/ECD complex was reported previously. The first structure of a class B GPCR transmembrane (TM) domain was solved recently, but the full length receptor structure is still not well understood. Here we describe the molecular details of antibody-mediated antagonism of the GLP-1R using both in vitro...... pharmacology and x-ray crystallography. We showed that the antibody Fab fragment (Fab 3F52) blocked the GLP-1 binding site of the ECD directly and thereby acts as a competitive antagonist of native GLP-1. Interestingly, Fab 3F52 also blocked a short peptide agonist believed to engage primarily...

  12. Glucocorticoid Antagonism Reduces Insulin Resistance and Associated Lipid Abnormalities in High-Fructose-Fed Mice.

    Science.gov (United States)

    Priyadarshini, Emayavaramban; Anuradha, Carani Venkatraman

    2017-02-01

    High intake of dietary fructose causes perturbation in lipid metabolism and provokes lipid-induced insulin resistance. A rise in glucocorticoids (GCs) has recently been suggested to be involved in fructose-induced insulin resistance. The objective of the study was to investigate the effect of GC blockade on lipid abnormalities in insulin-resistant mice. Insulin resistance was induced in mice by administering a high-fructose diet (HFrD) for 60 days. Mifepristone (RU486), a GC antagonist, was administered to HFrD-fed mice for the last 18 days, and the intracellular and extracellular GC levels, the glucocorticoid receptor (GR) activation and the expression of GC-regulated genes involved in lipid metabolism were examined. HFrD elevated the intracellular GC content in both liver and adipose tissue and enhanced the GR nuclear translocation. The plasma GC level remained unchanged. The levels of free fatty acids and triglycerides in plasma were elevated, accompanied by increased plasma insulin and glucose levels and decreased hepatic glycogen content. Treatment with RU486 reduced plasma lipid levels, tissue GC levels and the expression of GC-targeted genes involved in lipid accumulation, and it improved insulin sensitivity. This study demonstrated that HFrD-induced lipid accumulation and insulin resistance are mediated by enhanced GC in liver and adipose tissue and that GC antagonism might reduce fructose-induced lipid abnormalities and insulin resistance. Copyright © 2016 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.

  13. A Soluble Fluorescent Binding Assay Reveals PIP2 Antagonism of TREK-1 Channels

    Directory of Open Access Journals (Sweden)

    Cerrone Cabanos

    2017-08-01

    Full Text Available Lipid regulation of ion channels by low-abundance signaling lipids phosphatidylinositol 4,5-bisphosphate (PIP2 and phosphatidic acid (PA has emerged as a central cellular mechanism for controlling ion channels and the excitability of nerves. A lack of robust assays suitable for facile detection of a lipid bound to a channel has hampered the probing of the lipid binding sites and measuring the pharmacology of putative lipid agonists for ion channels. Here, we show a fluorescent PIP2 competition assay for detergent-purified potassium channels, including TWIK-1-related K+-channel (TREK-1. Anionic lipids PA and phosphatidylglycerol (PG bind dose dependently (9.1 and 96 μM, respectively and agonize the channel. Our assay shows PIP2 binds with high affinity (0.87 μM but surprisingly can directly antagonize TREK-1 in liposomes. We propose a model for TREK-1 lipid regulation where PIP2 can compete with PA and PG agonism based on the affinity of the lipid for a site within the channel.

  14. Wnt signalling antagonizes stress granule assembly through a Dishevelled-dependent mechanism

    Directory of Open Access Journals (Sweden)

    Pabitra K. Sahoo

    2012-02-01

    Cells often respond to diverse environmental stresses by inducing stress granules (SGs as an adaptive mechanism. SGs are generally assembled as a result of aggregation of mRNAs stalled in a translational pre-initiation complex, mediated by a set of RNA-binding proteins such as G3BP and TIA-1. SGs may serve as triage centres for storage, translation re-initiation or degradation of specific mRNAs. However, the mechanism involved in the modulation of their assembly/disassembly is unclear. Here we report that Wnt signalling negatively regulates SG assembly through Dishevelled (Dvl, a cytoplasmic Wnt effector. Overexpression of Dvl2, an isoform of Dvl, leads to impairment of SG assembly through a DEP domain dependent mechanism. Intriguingly, the Dvl2 mutant K446M, which corresponds to an analogous mutation in Drosophila Dishevelled DEP domain (dsh1 that results in defective PCP pathway, fails to antagonize SG assembly. Furthermore, we show that Dvl2 exerts the antagonistic effect on SG assembly through a mechanism involving Rac1-mediated inhibition of RhoA. Dvl2 interacts with G3BP, a downstream component of Ras signalling involved in SG assembly, and functional analysis suggests a model wherein the Dvl-Rac1-RhoA axis regulates G3BP's SG-nucleating activity. Collectively, these results define an antagonistic effect of Wnt signalling on SG assembly, and reveal a novel role for Wnt/Dvl pathway in the modulation of mRNA functions.

  15. Plant Essential Oils Synergize and Antagonize Toxicity of Different Conventional Insecticides against Myzus persicae (Hemiptera: Aphididae).

    Science.gov (United States)

    Faraone, Nicoletta; Hillier, N Kirk; Cutler, G Christopher

    2015-01-01

    Plant-derived products can play an important role in pest management programs. Essential oils from Lavandula angustifolia (lavender) and Thymus vulgaris (thyme) and their main constituents, linalool and thymol, respectively, were evaluated for insecticidal activity and synergistic action in combination with insecticides against green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae). The essential oils and their main constituents exerted similar insecticidal activity when aphids were exposed by direct sprays, but were non-toxic by exposure to treated leaf discs. In synergism experiments, the toxicity of imidacloprid was synergized 16- to 20-fold by L. angustifolia and T. vulgaris essential oils, but far less synergism occurred with linalool and thymol, indicating that secondary constituents of the oils were probably responsible for the observed synergism. In contrast to results with imidacloprid, the insecticidal activity of spirotetramat was antagonized by L. angustifolia and T. vulgaris essential oils, and linalool and thymol. Our results demonstrate the potential of plant essential oils as synergists of insecticides, but show that antagonistic action against certain insecticides may occur.

  16. Activating PTEN by COX-2 inhibitors antagonizes radiation-induced AKT activation contributing to radiosensitization

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Zhen [Central Laboratory, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing 100081 (China); Department of Oral & Maxillofacial Surgery, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing 100081 (China); Gan, Ye-Hua, E-mail: kqyehuagan@bjmu.edu.cn [Central Laboratory, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing 100081 (China); Department of Oral & Maxillofacial Surgery, Peking University School and Hospital of Stomatology, 22 Zhongguancun Avenue South, Haidian District, Beijing 100081 (China)

    2015-05-01

    Radiotherapy is still one of the most effective nonsurgical treatments for many tumors. However, radioresistance remains a major impediment to radiotherapy. Although COX-2 inhibitors can induce radiosensitization, the underlying mechanism is not fully understood. In this study, we showed that COX-2 selective inhibitor celecoxib enhanced the radiation-induced inhibition of cell proliferation and apoptosis in HeLa and SACC-83 cells. Treatment with celecoxib alone dephosphorylated phosphatase and tensin homolog deleted on chromosome ten (PTEN), promoted PTEN membrane translocation or activation, and correspondingly dephosphorylated or inactivated protein kinase B (AKT). By contrast, treatment with radiation alone increased PTEN phosphorylation, inhibited PTEN membrane translocation and correspondingly activated AKT in the two cell lines. However, treatment with celecoxib or another COX-2 selective inhibitor (valdecoxib) completely blocked radiation-induced increase of PTEN phosphorylation, rescued radiation-induced decrease in PTEN membrane translocation, and correspondingly inactivated AKT. Moreover, celecoxib could also upregulate PTEN protein expression by downregulating Sp1 expression, thereby leading to the activation of PTEN transcription. Our results suggested that COX-2 inhibitors could enhance radiosensitization at least partially by activating PTEN to antagonize radiation-induced AKT activation. - Highlights: • COX-2 inhibitor, celecoxib, could enhance radiosensitization. • Radiation induced PTEN inactivation (phosphorylation) and AKT activation. • COX-2 inhibitor induced PTEN expression and activation, and inactivated AKT. • COX-2 inhibitor enhanced radiosensitization through activating PTEN.

  17. Activating PTEN by COX-2 inhibitors antagonizes radiation-induced AKT activation contributing to radiosensitization

    International Nuclear Information System (INIS)

    Meng, Zhen; Gan, Ye-Hua

    2015-01-01

    Radiotherapy is still one of the most effective nonsurgical treatments for many tumors. However, radioresistance remains a major impediment to radiotherapy. Although COX-2 inhibitors can induce radiosensitization, the underlying mechanism is not fully understood. In this study, we showed that COX-2 selective inhibitor celecoxib enhanced the radiation-induced inhibition of cell proliferation and apoptosis in HeLa and SACC-83 cells. Treatment with celecoxib alone dephosphorylated phosphatase and tensin homolog deleted on chromosome ten (PTEN), promoted PTEN membrane translocation or activation, and correspondingly dephosphorylated or inactivated protein kinase B (AKT). By contrast, treatment with radiation alone increased PTEN phosphorylation, inhibited PTEN membrane translocation and correspondingly activated AKT in the two cell lines. However, treatment with celecoxib or another COX-2 selective inhibitor (valdecoxib) completely blocked radiation-induced increase of PTEN phosphorylation, rescued radiation-induced decrease in PTEN membrane translocation, and correspondingly inactivated AKT. Moreover, celecoxib could also upregulate PTEN protein expression by downregulating Sp1 expression, thereby leading to the activation of PTEN transcription. Our results suggested that COX-2 inhibitors could enhance radiosensitization at least partially by activating PTEN to antagonize radiation-induced AKT activation. - Highlights: • COX-2 inhibitor, celecoxib, could enhance radiosensitization. • Radiation induced PTEN inactivation (phosphorylation) and AKT activation. • COX-2 inhibitor induced PTEN expression and activation, and inactivated AKT. • COX-2 inhibitor enhanced radiosensitization through activating PTEN

  18. synMuv B proteins antagonize germline fate in the intestine and ensure C. elegans survival

    Science.gov (United States)

    Petrella, Lisa N.; Wang, Wenchao; Spike, Caroline A.; Rechtsteiner, Andreas; Reinke, Valerie; Strome, Susan

    2011-01-01

    Previous studies demonstrated that a subset of synMuv B mutants ectopically misexpress germline-specific P-granule proteins in their somatic cells, suggesting a failure to properly orchestrate a soma/germline fate decision. Surprisingly, this fate confusion does not affect viability at low to ambient temperatures. Here, we show that, when grown at high temperature, a majority of synMuv B mutants irreversibly arrest at the L1 stage. High temperature arrest (HTA) is accompanied by upregulation of many genes characteristic of germ line, including genes encoding components of the synaptonemal complex and other meiosis proteins. HTA is suppressed by loss of global regulators of germline chromatin, including MES-4, MRG-1, ISW-1 and the MES-2/3/6 complex, revealing that arrest is caused by somatic cells possessing a germline-like chromatin state. Germline genes are preferentially misregulated in the intestine, and necessity and sufficiency tests demonstrate that the intestine is the tissue responsible for HTA. We propose that synMuv B mutants fail to erase or antagonize an inherited germline chromatin state in somatic cells during embryonic and early larval development. As a consequence, somatic cells gain a germline program of gene expression in addition to their somatic program, leading to a mixed fate. Somatic expression of germline genes is enhanced at elevated temperature, leading to developmentally compromised somatic cells and arrest of newly hatched larvae. PMID:21343362

  19. Plant Essential Oils Synergize and Antagonize Toxicity of Different Conventional Insecticides against Myzus persicae (Hemiptera: Aphididae)

    Science.gov (United States)

    Faraone, Nicoletta; Hillier, N. Kirk; Cutler, G. Christopher

    2015-01-01

    Plant-derived products can play an important role in pest management programs. Essential oils from Lavandula angustifolia (lavender) and Thymus vulgaris (thyme) and their main constituents, linalool and thymol, respectively, were evaluated for insecticidal activity and synergistic action in combination with insecticides against green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae). The essential oils and their main constituents exerted similar insecticidal activity when aphids were exposed by direct sprays, but were non-toxic by exposure to treated leaf discs. In synergism experiments, the toxicity of imidacloprid was synergized 16- to 20-fold by L. angustifolia and T. vulgaris essential oils, but far less synergism occurred with linalool and thymol, indicating that secondary constituents of the oils were probably responsible for the observed synergism. In contrast to results with imidacloprid, the insecticidal activity of spirotetramat was antagonized by L. angustifolia and T. vulgaris essential oils, and linalool and thymol. Our results demonstrate the potential of plant essential oils as synergists of insecticides, but show that antagonistic action against certain insecticides may occur. PMID:26010088

  20. Plant Essential Oils Synergize and Antagonize Toxicity of Different Conventional Insecticides against Myzus persicae (Hemiptera: Aphididae.

    Directory of Open Access Journals (Sweden)

    Nicoletta Faraone

    Full Text Available Plant-derived products can play an important role in pest management programs. Essential oils from Lavandula angustifolia (lavender and Thymus vulgaris (thyme and their main constituents, linalool and thymol, respectively, were evaluated for insecticidal activity and synergistic action in combination with insecticides against green peach aphid, Myzus persicae (Sulzer (Hemiptera: Aphididae. The essential oils and their main constituents exerted similar insecticidal activity when aphids were exposed by direct sprays, but were non-toxic by exposure to treated leaf discs. In synergism experiments, the toxicity of imidacloprid was synergized 16- to 20-fold by L. angustifolia and T. vulgaris essential oils, but far less synergism occurred with linalool and thymol, indicating that secondary constituents of the oils were probably responsible for the observed synergism. In contrast to results with imidacloprid, the insecticidal activity of spirotetramat was antagonized by L. angustifolia and T. vulgaris essential oils, and linalool and thymol. Our results demonstrate the potential of plant essential oils as synergists of insecticides, but show that antagonistic action against certain insecticides may occur.

  1. Innate immune restriction and antagonism of viral RNA lacking 2'-O methylation

    Energy Technology Data Exchange (ETDEWEB)

    Hyde, Jennifer L. [Departments of Medicine, Washington University School of Medicine, St Louis., MO 63110 (United States); Diamond, Michael S., E-mail: diamond@borcim.wustl.edu [Departments of Medicine, Washington University School of Medicine, St Louis., MO 63110 (United States); Molecular Microbiology, Washington University School of Medicine, St Louis., MO 63110 (United States); Pathology & Immunology, Washington University School of Medicine, St Louis., MO 63110 (United States); The Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St Louis., MO 63110 (United States)

    2015-05-15

    N-7 and 2′-O methylation of host cell mRNA occurs in the nucleus and results in the generation of cap structures (cap 0, m{sup 7}GpppN; cap 1, m{sup 7}GpppNm) that control gene expression by modulating nuclear export, splicing, turnover, and protein synthesis. Remarkably, RNA cap modification also contributes to mammalian cell host defense as viral RNA lacking 2′-O methylation is sensed and inhibited by IFIT1, an interferon (IFN) stimulated gene (ISG). Accordingly, pathogenic viruses that replicate in the cytoplasm have evolved mechanisms to circumvent IFIT1 restriction and facilitate infection of mammalian cells. These include: (a) generating cap 1 structures on their RNA through cap-snatching or virally-encoded 2′-O methyltransferases, (b) using cap-independent means of translation, or (c) using RNA secondary structural motifs to antagonize IFIT1 binding. This review will discuss new insights as to how specific modifications at the 5′-end of viral RNA modulate host pathogen recognition responses to promote infection and disease.

  2. Caffeine intake antagonizes salt sensitive hypertension through improvement of renal sodium handling.

    Science.gov (United States)

    Yu, Hao; Yang, Tao; Gao, Peng; Wei, Xing; Zhang, Hexuan; Xiong, Shiqiang; Lu, Zongshi; Li, Li; Wei, Xiao; Chen, Jing; Zhao, Yu; Arendshorst, William J; Shang, Qianhui; Liu, Daoyan; Zhu, Zhiming

    2016-05-12

    High salt intake is a major risk factor for hypertension. Although acute caffeine intake produces moderate diuresis and natriuresis, caffeine increases the blood pressure (BP) through activating sympathetic activity. However, the long-term effects of caffeine on urinary sodium excretion and blood pressure are rarely investigated. Here, we investigated whether chronic caffeine administration antagonizes salt sensitive hypertension by promoting urinary sodium excretion. Dahl salt-sensitive (Dahl-S) rats were fed with high salt diet with or without 0.1% caffeine in drinking water for 15 days. The BP, heart rate and locomotor activity of rats was analyzed and urinary sodium excretion was determined. The renal epithelial Na(+) channel (ENaC) expression and function were measured by in vivo and in vitro experiments. Chronic consumption of caffeine attenuates hypertension induced by high salt without affecting sympathetic nerve activity in Dahl-S rats. The renal α-ENaC expression and ENaC activity of rats decreased after chronic caffeine administration. Caffeine increased phosphorylation of AMPK and decrease α-ENaC expression in cortical collecting duct cells. Inhibiting AMPK abolished the effect of caffeine on α-ENaC. Chronic caffeine intake prevented the development of salt-sensitive hypertension through promoting urinary sodium excretion, which was associated with activation of renal AMPK and inhibition of renal tubular ENaC.

  3. Antagonizing beta-amyloid peptide neurotoxicity of the anti-aging fungus Ganoderma lucidum.

    Science.gov (United States)

    Lai, Cora Sau-Wan; Yu, Man-Shan; Yuen, Wai-Hung; So, Kwok-Fai; Zee, Sze-Yong; Chang, Raymond Chuen-Chung

    2008-01-23

    Ganoderma lucidum (Leyss. ex Fr.) Karst. (Lingzhi) is a medicinal fungus used clinically in many Asian countries to promote health and longevity. Synaptic degeneration is another key mode of neurodegeneration in Alzheimer's disease (AD). Recent studies have shown the loss of synaptic density proteins in each individual neuron during the progression of AD. It was recently reported that beta-amyloid (Abeta) could cause synaptic dysfunction and contribute to AD pathology. In this study, we reported that aqueous extract of G. lucidum significantly attenuated Abeta-induced synaptotoxicity by preserving the synaptic density protein, synaptophysin. In addition, G. lucidum aqueous extract antagonized Abeta-triggered DEVD cleavage activities in a dose-dependent manner. Further studies elucidated that phosphorylation of c-Jun N-terminal kinase, c-Jun, and p38 MAP kinase was attenuated by G. lucidum in Abeta-stressed neurons. Taken together, the results prove a hypothesis that anti-aging G. lucidum can prevent harmful effects of the exterminating toxin Abeta in AD.

  4. MCT1 promotes the cisplatin-resistance by antagonizing Fas in epithelial ovarian cancer.

    Science.gov (United States)

    Yan, Chunxiao; Yang, Fan; Zhou, Chunxia; Chen, Xuejun; Han, Xuechuan; Liu, Xueqin; Ma, Hongyun; Zheng, Wei

    2015-01-01

    This study was designed to investigate the role of MCT1 in the development of cisplatin-resistant ovarian cancer and its possible relationship with Fas. We found the expression of MCT1 was obviously increased both in cisplatin-resistant ovarian cancer tissue and A2780/CP cells compared with sensitive ovarian cancer tissue and cell lines A2780. And in A2780 cells treated with Cisplatin, the expression of MCT1 increased in a concentration-dependent manner, MCT1 knockdown attenuates cisplatin-induced cell viability. In A2780 and A2780/CP cells transfected with MCT1 siRNA, the activation of several downstream targets of Fas, including FasL and FAP-1 were largely prevented, whereas the expression of Caspase-3 was increased, accompanying with increased abundance of Fas. Coimmunoprecipitation and immunofluorescence showed that there is interaction between endogenous MCT1 with Fas in vivo and in vitro. In vivo, depletion of MCT1 by shRNA reverses cisplatin-resistance and the expression of Fas. This study showed that down regulation of MCT1 promote the sensibility to Cisplatin in ovarian cancer cell line. And this effect appeared to be mediated via antagonizing the effect of Fas.

  5. Cardiovascular and behavioral responses of gray wolves to ketamine-xylazine immobilization and antagonism by yohimbine

    Science.gov (United States)

    Kreeger, T.J.; Faggella, A.M.; Seal, U.S.; Mech, L.D.; Callahan, Margaret; Hall, B.

    1987-01-01

    Adult wolves (Canis lupus) were immobilized with 6.6 mg/kg ketamine hydrochloride (KET) and 2.2 mg/kg xylazine hydrochloride (XYL) administered intramuscularly. Induction time was 4.6 ± 0.3 min (x̄ ± SE). Immobilization resulted in significant bradycardia and hypertension (P 0.15 mg/kg resulting in extreme tachycardia (>300 bpm). All doses of YOH caused a temporary decrease in mean arterial blood pressure (MABP) with some individual animals manifesting profound hypotension (0.15 mg/kg. Increasing the dose of YOH above 0.15 mg/kg did not significantly decrease either arousal or ambulation times. Administering YOH at 40 or 60 min after induction resulted in decreased arousal and ambulation times. Stimulation by weighing and taking repeated blood samples during anesthesia did not shorten arousal times. We recommend that wolves immobilized with XYL-KET be antagonized with doses of YOH <0.15 mg/kg.

  6. Action of Bacopa monnieri to antagonize cisplatin-induced emesis in Suncus murinus (house musk shrew

    Directory of Open Access Journals (Sweden)

    Ihsan Ullah

    2017-04-01

    Full Text Available Bacopa monnieri (BM, family Scrophulariaceae is used in several traditional systems of medicine for the management of epilepsy, depression, neuropathic pain, sleep disorders and memory deficits. The present study investigated the potential of BM methanol (BM-MetFr and BM n-butanol fractions (BM-ButFr to reduce chemotherapy-induced emesis in Suncus murinus (house musk shrew. Cisplatin (30 mg/kg, i.p. reliably induced retching and/or vomiting over a 2 day period. BM-MetFr (10–40 mg/kg, s.c. and BM-ButFr (5–20 mg/kg, s.c. antagonized the retching and/or vomiting response by ∼59.4% (p  0.05. In conclusion, the n-butanol fractions of BM have anti-emetic activity comparable with palonosetron and MPG. BM may be useful alone or in combination with other anti-emetic drugs for the treatment of chemotherapy-induced emesis in man.

  7. TRPV1 Antagonism by Capsazepine Modulates Innate Immune Response in Mice Infected with Plasmodium berghei ANKA

    Directory of Open Access Journals (Sweden)

    Elizabeth S. Fernandes

    2014-01-01

    Full Text Available Thousands of people suffer from severe malaria every year. The innate immune response plays a determinant role in host’s defence to malaria. Transient receptor potential vanilloid 1 (TRPV1 modulates macrophage-mediated responses in sepsis, but its role in other pathogenic diseases has never been addressed. We investigated the effects of capsazepine, a TRPV1 antagonist, in malaria. C57BL/6 mice received 105 red blood cells infected with Plasmodium berghei ANKA intraperitoneally. Noninfected mice were used as controls. Capsazepine or vehicle was given intraperitoneally for 6 days. Mice were culled on day 7 after infection and blood and spleen cell phenotype and activation were evaluated. Capsazepine decreased circulating but not spleen F4/80+Ly6G+ cell numbers as well as activation of both F4/80+and F4/80+Ly6G+ cells in infected animals. In addition, capsazepine increased circulating but not spleen GR1+ and natural killer (NK population, without interfering with natural killer T (NKT cell numbers and blood NK and NKT activation. However, capsazepine diminished CD69 expression in spleen NKT but not NK cells. Infection increased lipid peroxidation and the release of TNFα and IFNγ, although capsazepine-treated group exhibited lower levels of lipid peroxidation and TNFα. Capsazepine treatment did not affect parasitaemia. Overall, TRPV1 antagonism modulates the innate immune response to malaria.

  8. Deubiquitinase USP13 maintains glioblastoma stem cells by antagonizing FBXL14-mediated Myc ubiquitination

    Science.gov (United States)

    Zhou, Wenchao; Mack, Stephen C.; Wang, Xiuxing; Ouyang, Gaoliang; Bian, Xiu-wu

    2017-01-01

    Glioblastoma is the most lethal brain tumor and harbors glioma stem cells (GSCs) with potent tumorigenic capacity. The function of GSCs in tumor propagation is maintained by several core transcriptional regulators including c-Myc. c-Myc protein is tightly regulated by posttranslational modification. However, the posttranslational regulatory mechanisms for c-Myc in GSCs have not been defined. In this study, we demonstrate that the deubiquitinase USP13 stabilizes c-Myc by antagonizing FBXL14-mediated ubiquitination to maintain GSC self-renewal and tumorigenic potential. USP13 was preferentially expressed in GSCs, and its depletion potently inhibited GSC proliferation and tumor growth by promoting c-Myc ubiquitination and degradation. In contrast, overexpression of the ubiquitin E3 ligase FBXL14 induced c-Myc degradation, promoted GSC differentiation, and inhibited tumor growth. Ectopic expression of the ubiquitin-insensitive mutant T58A–c-Myc rescued the effects caused by FBXL14 overexpression or USP13 disruption. These data suggest that USP13 and FBXL14 play opposing roles in the regulation of GSCs through reversible ubiquitination of c-Myc. PMID:27923907

  9. E1B and E4 oncoproteins of adenovirus antagonize the effect of apoptosis inducing factor

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Roberta L. [Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157 (United States); Wilkinson, John C., E-mail: john.wilkinson@ndsu.edu [Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157 (United States); Ornelles, David A., E-mail: ornelles@wakehealth.edu [Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157 (United States)

    2014-05-15

    Adenovirus inundates the productively infected cell with linear, double-stranded DNA and an abundance of single-stranded DNA. The cellular response to this stimulus is antagonized by the adenoviral E1B and E4 early genes. A mutant group C adenovirus that fails to express the E1B-55K and E4ORF3 genes is unable to suppress the DNA-damage response. Cells infected with this double-mutant virus display significant morphological heterogeneity at late times of infection and frequently contain fragmented nuclei. Nuclear fragmentation was due to the translocation of apoptosis inducing factor (AIF) from the mitochondria into the nucleus. The release of AIF was dependent on active poly(ADP-ribose) polymerase-1 (PARP-1), which appeared to be activated by viral DNA replication. Nuclear fragmentation did not occur in AIF-deficient cells or in cells treated with a PARP-1 inhibitor. The E1B-55K or E4ORF3 proteins independently prevented nuclear fragmentation subsequent to PARP-1 activation, possibly by altering the intracellular distribution of PAR-modified proteins. - Highlights: • E1B-55K or E4orf3 prevents nuclear fragmentation. • Nuclear fragmentation requires AIF and PARP-1 activity. • Adenovirus DNA replication activates PARP-1. • E1B-55K or E4orf3 proteins alter the distribution of PAR.

  10. Leptin Antagonizes Peroxisome Proliferator-Activated Receptor-γ Signaling in Growth Plate Chondrocytes

    Directory of Open Access Journals (Sweden)

    Lai Wang

    2012-01-01

    Full Text Available Leptin is an obesity-associated cytokine-like hormone encoded by the ob gene. Recent studies reveal that leptin promotes proliferation and differentiation of chondrocytes, suggesting a peripheral role of leptin in regulating growth plate function. Peroxisome proliferator-activated receptor-γ (PPARγ is a transcriptional regulator of adipogenesis. Locally, PPARγ negatively regulates chondrogenic differentiation and terminal differentiation in the growth plate. The aim of this study was to test the hypothesis that leptin may suppress the inhibitory effects of PPARγ on growth plate chondrocytes. Chondrocytes were collected from distal femoral growth plates of newborn rats and were cultured in monolayer or cell pellets in the presence or absence of leptin and the PPARγ agonist ciglitazone. The results show that leptin attenuates the suppressive effects of PPARγ on chondrogenic differentiation and T3-mediated chondrocyte hypertrophy. Leptin treatment also leads to a mild downregulation of PPAR mRNA expression and a significant MAPK/ERK-dependent PPARγ phosphorylation at serine 112/82. Blocking MAPK/ERK function with PD98059 confirmed that leptin antagonizes PPARγ function in growth plate chondrocytes through the MAPK/ERK signaling pathway. Furthermore, leptin signaling in growth plate cells is also negatively modulated by activation of PPARγ, implying that these two signaling pathways are mutually regulated in growth plate chondrocytes.

  11. Antagonism of Apis mellifera and Melipona beecheii for the sources of feeding

    Directory of Open Access Journals (Sweden)

    Ailyn Leal-Ramos

    2013-12-01

    Full Text Available The competition is defined as the interrelation among species that influence negatively in the abundance or the growth of the population of an or both species. They can be defined two competition types: competition of exploitation for the use of a resource shared as the food and the competition by interference when decreases the efficiency of exploitation of another species for the competition for the territory. With the objective of determining the possible antagonism of A. mellifera and M. beecheii for the source of pollen, the origin of the pollen stored in the reservations of foods of the beehives of A. mellifera and M. beecheii through palinologic analysis carried out to samples of pollen of both species of bees settled down. The diversity of pollen found in the samples is superior in A. mellifera with regard to M. beecheii being Mimosa pudica and Mimosa pigra the identified species with a high frequency. On the other hand, 71,4% of the vegetable identified species coincides in the pollen found in the samples of A. mellifera and M. beecheii, being a half similarity among the grains of pollen of the beehives of both species expressed by a coefficient of similarity of Jaccard 0,5219.

  12. Innate immune restriction and antagonism of viral RNA lacking 2׳-O methylation.

    Science.gov (United States)

    Hyde, Jennifer L; Diamond, Michael S

    2015-05-01

    N-7 and 2'-O methylation of host cell mRNA occurs in the nucleus and results in the generation of cap structures (cap 0, m(7)GpppN; cap 1, m(7)GpppNm) that control gene expression by modulating nuclear export, splicing, turnover, and protein synthesis. Remarkably, RNA cap modification also contributes to mammalian cell host defense as viral RNA lacking 2'-O methylation is sensed and inhibited by IFIT1, an interferon (IFN) stimulated gene (ISG). Accordingly, pathogenic viruses that replicate in the cytoplasm have evolved mechanisms to circumvent IFIT1 restriction and facilitate infection of mammalian cells. These include: (a) generating cap 1 structures on their RNA through cap-snatching or virally-encoded 2'-O methyltransferases, (b) using cap-independent means of translation, or (c) using RNA secondary structural motifs to antagonize IFIT1 binding. This review will discuss new insights as to how specific modifications at the 5'-end of viral RNA modulate host pathogen recognition responses to promote infection and disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. The antagonic effect of iron and zinc in formulations of feeding diets studied by response surface methodology for mixtures

    OpenAIRE

    BUENO, Luciana

    2008-01-01

    Nutritional therapy with enteral diets became substantially specialized over the last years. This work's aim was to study the effect of the components of a formulation: fiber, calcium and medium-chain triglycerides for dialysability of minerals. Analysis of multiple variables was carried out using response surface methodology. The level curve showed an antagonic effect of interaction between iron and zinc. TCM was the variable responsible for characterizing competition between the two mineral...

  14. P2X7 Receptor Antagonism Attenuates the Intermittent Hypoxia-induced Spatial Deficits in a Murine Model of Sleep Apnea Via Inhibiting Neuroinflammation and Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Yan Deng

    2015-01-01

    Conclusions: The P2X7R antagonism attenuates the CIH-induced neuroinflammation, oxidative stress, and spatial deficits, demonstrating that the P2X7R is an important therapeutic target in the cognition deficits accompanied OSAS.

  15. Transmissible Gastroenteritis Virus Papain-Like Protease 1 Antagonizes Production of Interferon-βthrough Its Deubiquitinase Activity.

    Science.gov (United States)

    Hu, Xiaoliang; Tian, Jin; Kang, Hongtao; Guo, Dongchun; Liu, Jiasen; Liu, Dafei; Jiang, Qian; Li, Zhijie; Qu, Juanjuan; Qu, Liandong

    2017-01-01

    Coronaviruses (CoVs), such as human coronavirus NL63 (HCoV-NL63), severe acute respiratory syndrome CoV (SARS-CoV), murine hepatitis virus (MHV), porcine epidemic diarrhea virus (PEDV), and Middle East Respiratory Syndrome Coronavirus (MERS-CoV), encode papain-like (PL) proteases that inhibit Sendai virus- (SeV-) induced interferon (IFN- β ) production. Recently, the crystal structure of transmissible gastroenteritis virus (TGEV) PL1 has been solved, which was similar to that of SARS-CoV PL2 pro , which may antagonize host innate immunity. However, very little is known about whether TGEV PL1 can antagonize host innate immune response. Here, we presented evidence that TGEV PL1 encoded by the replicase gene could suppress the IFN- β expression and inhibit the nuclear translocation of interferon regulatory factor 3 (IRF3). The ability to antagonize IFN- β production was dependent on the intact catalytic activity of PL1. Furthermore, TGEV PL1 exerted deubiquitinase (DUB) activity which strongly inhibited the retinoic acid-induced gene I- (RIG-1-) and stimulator of interferon gene- (STING-) dependent IFN expression. Our data collectively suggest that TGEV PL1 can inhibit the IFN- β expression and interfere with RIG-1- and STING-mediated signaling through a viral DUB activity. Our study has yielded strong evidence for the TGEV PL1 mechanisms that counteract the host innate immunity.

  16. Transmissible Gastroenteritis Virus Papain-Like Protease 1 Antagonizes Production of Interferon-β through Its Deubiquitinase Activity

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    Xiaoliang Hu

    2017-01-01

    Full Text Available Coronaviruses (CoVs, such as human coronavirus NL63 (HCoV-NL63, severe acute respiratory syndrome CoV (SARS-CoV, murine hepatitis virus (MHV, porcine epidemic diarrhea virus (PEDV, and Middle East Respiratory Syndrome Coronavirus (MERS-CoV, encode papain-like (PL proteases that inhibit Sendai virus- (SeV- induced interferon (IFN-β production. Recently, the crystal structure of transmissible gastroenteritis virus (TGEV PL1 has been solved, which was similar to that of SARS-CoV PL2pro, which may antagonize host innate immunity. However, very little is known about whether TGEV PL1 can antagonize host innate immune response. Here, we presented evidence that TGEV PL1 encoded by the replicase gene could suppress the IFN-β expression and inhibit the nuclear translocation of interferon regulatory factor 3 (IRF3. The ability to antagonize IFN-β production was dependent on the intact catalytic activity of PL1. Furthermore, TGEV PL1 exerted deubiquitinase (DUB activity which strongly inhibited the retinoic acid-induced gene I- (RIG-1- and stimulator of interferon gene- (STING- dependent IFN expression. Our data collectively suggest that TGEV PL1 can inhibit the IFN-β expression and interfere with RIG-1- and STING-mediated signaling through a viral DUB activity. Our study has yielded strong evidence for the TGEV PL1 mechanisms that counteract the host innate immunity.

  17. Minimal structural requirements of alkyl γ-lactones capable of antagonizing the cocaine-induced motility decrease in planarians.

    Science.gov (United States)

    Baker, Debra; Deats, Sean; Boor, Peter; Pruitt, James; Pagán, Oné R

    2011-11-01

    We recently reported that the natural cyclic lactone, parthenolide, and related analogs prevent the expression of behavioral effects induced by cocaine in planarians and that parthenolide's γ-lactone ring is required for this effect. In the present work, we tested a series of alkyl γ-lactones with varying chain length (1-8 carbons) to determine their ability to antagonize the planarian motility decrease induced by 200 μM cocaine. Alkyl lactones with up to a 4-carbon alkyl chain did not affect planarian motility or antagonized the cocaine-induced motility decrease; only the compound γ-nonalactone (a γ-lactone with a 5-carbon chain) was able to prevent the cocaine-induced behavioral patterns, while alkyl lactones with longer carbon chains failed to prevent the cocaine-induced effects. Thus, we conclude that the optimal structural features of this family of compounds to antagonize cocaine's effect in this experimental system is a γ-lactone ring with at a 5-carbon long functional group. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Identification of up-regulated proteins potentially involved in the antagonism mechanism of Bacillus amyloliquefaciens G1.

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    Cao, Haipeng; Zheng, Weidong; He, Shan; Wang, Hao; Wang, Tu; Lu, Liqun

    2013-06-01

    The use of Bacillus probiotics has been demonstrated as a promising method in the biocontrol of bacterial diseases in aquaculture. However, the molecular antibacterial mechanism of Bacillus still remains unclear. In order to explore the antibacterial mechanism of the potential antagonistic Bacillus amyloliquefaciens strain G1, comparative proteomics between B. amyloliquefaciens strain G1 and its non-antagonistic mutant strain was investigated. The 2-dimensional electrophoresis gel maps of their total extracted proteins were described and 42 different proteins were found to be highly expressed in strain G1 in comparison with those in the mutant strain. 35 of these up-regulated proteins were successfully identified using MALDI-TOF-TOF MS and databank analysis, and their biological functions were analyzed through the KEGG database. The increased expression of these proteins suggested that high levels of energy metabolism, biosynthesis and stress resistance could play important roles in strain G1's antagonism. To our knowledge, this is the first report on the proteins involved in the antagonism mechanism of B. amyloliquefaciens using a proteomic approach and the proteomic data also contribute to a better understanding of the molecular basis for the antagonism of B. amyloliquefaciens.

  19. Antagonism of Nav channels and α1-adrenergic receptors contributes to vascular smooth muscle effects of ranolazine.

    Science.gov (United States)

    Virsolvy, Anne; Farah, Charlotte; Pertuit, Nolwenn; Kong, Lingyan; Lacampagne, Alain; Reboul, Cyril; Aimond, Franck; Richard, Sylvain

    2015-12-10

    Ranolazine is a recently developed drug used for the treatment of patients with chronic stable angina. It is a selective inhibitor of the persistent cardiac Na(+) current (INa), and is known to reduce the Na(+)-dependent Ca(2+) overload that occurs in cardiomyocytes during ischemia. Vascular effects of ranolazine, such as vasorelaxation,have been reported and may involve multiple pathways. As voltage-gated Na(+) channels (Nav) present in arteries play a role in contraction, we hypothesized that ranolazine could target these channels. We studied the effects of ranolazine in vitro on cultured aortic smooth muscle cells (SMC) and ex vivo on rat aortas in conditions known to specifically activate or promote INa. We observed that in the presence of the Nav channel agonist veratridine, ranolazine inhibited INa and intracellular Ca(2+) calcium increase in SMC, and arterial vasoconstriction. In arterial SMC, ranolazine inhibited the activity of tetrodotoxin-sensitive voltage-gated Nav channels and thus antagonized contraction promoted by low KCl depolarization. Furthermore, the vasorelaxant effects of ranolazine, also observed in human arteries and independent of the endothelium, involved antagonization of the α1-adrenergic receptor. Combined α1-adrenergic antagonization and inhibition of SMCs Nav channels could be involved in the vascular effects of ranolazine.

  20. An Improved Brome mosaic virus Silencing Vector: Greater Insert Stability and More Extensive VIGS1[OPEN

    Science.gov (United States)

    2018-01-01

    Virus-induced gene silencing (VIGS) is used extensively for gene function studies in plants. VIGS is inexpensive and rapid compared with silencing conducted through stable transformation, but many virus-silencing vectors, especially in grasses, induce only transient silencing phenotypes. A major reason for transient phenotypes is the instability of the foreign gene fragment (insert) in the vector during VIGS. Here, we report the development of a Brome mosaic virus (BMV)-based vector that better maintains inserts through modification of the original BMV vector RNA sequence. Modification of the BMV RNA3 sequence yielded a vector, BMVCP5, that better maintained phytoene desaturase and heat shock protein70-1 (HSP70-1) inserts in Nicotiana benthamiana and maize (Zea mays). Longer maintenance of inserts was correlated with greater target gene silencing and more extensive visible silencing phenotypes displaying greater tissue penetration and involving more leaves. The modified vector accumulated similarly to the original vector in N. benthamiana after agroinfiltration, thus maintaining a high titer of virus in this intermediate host used to produce virus inoculum for grass hosts. For HSP70, silencing one family member led to a large increase in the expression of another family member, an increase likely related to the target gene knockdown and not a general effect of virus infection. The cause of the increased insert stability in the modified vector is discussed in relationship to its recombination and accumulation potential. The modified vector will improve functional genomic studies in grasses, and the conceptual methods used to improve the vector may be applied to other VIGS vectors. PMID:29127260

  1. The impact of organizational culture on employees’ organizational silence In Shiraz University of Medical Sciences

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    Ebrahim Parcham

    2017-01-01

    Full Text Available Introduction: Organizational Culture is one of the most important factors that can change the climate of silence. The main aim of this research was to investigate the influence of organizational culture on employees’ organizational silence in Shiraz University of Medical Sciences. Method: This research was a descriptive-correlation one. The target population was chosen from 1900 staff of the University of Medical sciences and Health Care headquarter in Shiraz. Thus 311 employees were selected using the Krejcie and Morgan sampling table. The instrument used in this research was Denison (2006 organizational culture questionnaire and Dimitris Buratas and Maria Vacula (2007 organizational culture. Cornbrash’s alpha method was used to calculate the reliability. The Item analysis and expert consensus were applied to calculate the validity of instruments. All gathered data analyzed with PLS software. Results: The results showed that the four dimensions of organizational culture include organizational involvement, organizational adaptability, organizational concistency and organizational mission was moderate and the mean scores obtained for each factor were 2.85, 2.82, 2.94 and 2.93 respectively. Structural equation model showed Organizational culture has a significant positive impact on organizational silence (β=0.68; P<.001. Conclusion: Based on the results and impact of organizational culture on organizational silence that is positive and significant; The organization further efforts to strengthen various aspects of organizational culture, especially the employees’ involvement in decision making; Employees can better express their opinions and thus reduced their organizational silence. In other words strengthening corporate culture is combined with the reduction of organizational silence. Medical organizations can establish appropriate reward system for creative ideas and suggestions to encourage people express their ideas As a result, reduced

  2. An ImprovedBrome mosaic virusSilencing Vector: Greater Insert Stability and More Extensive VIGS.

    Science.gov (United States)

    Ding, Xin Shun; Mannas, Stephen W; Bishop, Bethany A; Rao, Xiaolan; Lecoultre, Mitchell; Kwon, Soonil; Nelson, Richard S

    2018-01-01

    Virus-induced gene silencing (VIGS) is used extensively for gene function studies in plants. VIGS is inexpensive and rapid compared with silencing conducted through stable transformation, but many virus-silencing vectors, especially in grasses, induce only transient silencing phenotypes. A major reason for transient phenotypes is the instability of the foreign gene fragment (insert) in the vector during VIGS. Here, we report the development of a Brome mosaic virus (BMV)-based vector that better maintains inserts through modification of the original BMV vector RNA sequence. Modification of the BMV RNA3 sequence yielded a vector, BMVCP5, that better maintained phytoene desaturase and heat shock protein70-1 ( HSP70-1 ) inserts in Nicotiana benthamiana and maize ( Zea mays ). Longer maintenance of inserts was correlated with greater target gene silencing and more extensive visible silencing phenotypes displaying greater tissue penetration and involving more leaves. The modified vector accumulated similarly to the original vector in N. benthamiana after agroinfiltration, thus maintaining a high titer of virus in this intermediate host used to produce virus inoculum for grass hosts. For HSP70 , silencing one family member led to a large increase in the expression of another family member, an increase likely related to the target gene knockdown and not a general effect of virus infection. The cause of the increased insert stability in the modified vector is discussed in relationship to its recombination and accumulation potential. The modified vector will improve functional genomic studies in grasses, and the conceptual methods used to improve the vector may be applied to other VIGS vectors. © 2018 American Society of Plant Biologists. All Rights Reserved.

  3. Development of a gene silencing DNA vector derived from a broad host range geminivirus

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    Hancock Leandria C

    2009-07-01

    Full Text Available Abstract Background Gene silencing is proving to be a powerful tool for genetic, developmental, and physiological analyses. The use of viral induced gene silencing (VIGS offers advantages to transgenic approaches as it can be potentially applied to non-model systems for which transgenic techniques are not readily available. However, many VIGS vectors are derived from Gemini viruses that have limited host ranges. We present a new, unipartite vector that is derived from a curtovirus that has a broad host range and will be amenable to use in many non-model systems. Results The construction of a gene silencing vector derived from the geminivirus Beet curly top virus (BCTV, named pWSRi, is reported. Two versions of the vector have been developed to allow application by biolistic techniques or by agro-infiltration. We demonstrate its ability to silence nuclear genes including ribulose bisphosphate carboxylase small subunit (rbcS, transketolase, the sulfur allele of magnesium chelatase (ChlI, and two homeotic transcription factors in spinach or tomato by generating gene-specific knock-down phenotypes. Onset of phenotypes occurred 3 to 12 weeks post-inoculation, depending on the target gene, in organs that developed after the application. The vector lacks movement genes and we found no evidence for significant spread from the site of inoculation. However, viral amplification in inoculated tissue was detected and is necessary for systemic silencing, suggesting that signals generated from active viral replicons are efficiently transported within the plant. Conclusion The unique properties of the pWSRi vector, the ability to silence genes in meristem tissue, the separation of virus and silencing phenotypes, and the broad natural host range of BCTV, suggest that it will have wide utility.

  4. On the acoustic performance of rectangular splitter silencers in the presence of mean flow

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    Kirby, Ray; Amott, Ken; Williams, Paul T.; Duan, Wenbo

    2014-12-01

    Dissipative splitter silencers are often used to reduce the noise emitted in ventilation and gas turbine systems. It is well known that the acoustic performance of a splitter silencer changes under the influence of the convective effects of a mean gas flow and so in this article a theoretical model is developed to include the effects of mean flow. The theoretical model is based on a hybrid finite element method which enables the inclusion of bull nose fairings and a perforated screen separating the mean gas flow from a bulk reacting porous material. Predictions are compared against experimental measurements obtained both with and without mean flow. Good agreement between prediction and measurement is generally observed in the absence of mean flow, although it is seen that for silencers with a low percentage open area the silencer insertion loss is over predicted at higher frequencies. When mean flow is present, problems with the experimental methodology are observed at relatively modest mean flow velocities, and so comparison between prediction and experiment is limited to relatively low face velocities. However, experiment and theory both show that the insertion loss reduces at low frequencies when mean flow is in the direction of sound propagation, and at high frequencies the influence of mean flow is generally much smaller. Following additional theoretical investigations it is concluded that the influence of mean flow on splitter silencer performance should be accounted for at low frequencies when silencer airway velocities are greater than about 20 m/s; however, at higher frequencies one may generally neglect the effect of mean flow, even at higher velocities. Predictions obtained using the hybrid method are also compared to a simplified point collocation approach and it is demonstrated that the computationally efficient point collocation method may be used to investigate the effects of mean flow in a splitter silencer without loss of accuracy.

  5. Specific tandem repeats are sufficient for paramutation-induced trans-generational silencing.

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    Christiane L Belele

    Full Text Available Paramutation is a well-studied epigenetic phenomenon in which trans communication between two different alleles leads to meiotically heritable transcriptional silencing of one of the alleles. Paramutation at the b1 locus involves RNA-mediated transcriptional silencing and requires specific tandem repeats that generate siRNAs. This study addressed three important questions: 1 are the tandem repeats sufficient for paramutation, 2 do they need to be in an allelic position to mediate paramutation, and 3 is there an association between the ability to mediate paramutation and repeat DNA methylation levels? Paramutation was achieved using multiple transgenes containing the b1 tandem repeats, including events with tandem repeats of only one half of the repeat unit (413 bp, demonstrating that these sequences are sufficient for paramutation and an allelic position is not required for the repeats to communicate. Furthermore, the transgenic tandem repeats increased the expression of a reporter gene in maize, demonstrating the repeats contain transcriptional regulatory sequences. Transgene-mediated paramutation required the mediator of paramutation1 gene, which is necessary for endogenous paramutation, suggesting endogenous and transgene-mediated paramutation both require an RNA-mediated transcriptional silencing pathway. While all tested repeat transgenes produced small interfering RNAs (siRNAs, not all transgenes induced paramutation suggesting that, as with endogenous alleles, siRNA production is not sufficient for paramutation. The repeat transgene-induced silencing was less efficiently transmitted than silencing induced by the repeats of endogenous b1 alleles, which is always 100% efficient. The variability in the strength of the repeat transgene-induced silencing enabled testing whether the extent of DNA methylation within the repeats correlated with differences in efficiency of paramutation. Transgene-induced paramutation does not require extensive

  6. Development of RNA Interference Trigger-Mediated Gene Silencing in Entamoeba invadens.

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    Suresh, Susmitha; Ehrenkaufer, Gretchen; Zhang, Hanbang; Singh, Upinder

    2016-04-01

    Entamoeba histolytica, a protozoan parasite, is an important human pathogen and a leading parasitic cause of death. The organism has two life cycle stages, trophozoites, which are responsible for tissue invasion, and cysts, which are involved in pathogen transmission. Entamoeba invadens is the model system to study Entamoeba developmental biology, as high-grade regulated encystation and excystation are readily achievable. However, the lack of gene-silencing tools in E. invadens has limited the molecular studies that can be performed. Using the endogenous RNA interference (RNAi) pathway in Entamoeba, we developed an RNAi-based trigger gene-silencing approach inE. invadens We demonstrate that a gene's coding region that has abundant antisense small RNAs (sRNAs) can trigger silencing of a gene that is fused to it. The trigger fusion leads to the generation of abundant antisense sRNAs that map to the target gene, with silencing occurring independently of trigger location at the 5' or 3' end of a gene. Gene silencing is stably maintained during development, including encystation and excystation. We have used this approach to successfully silence two E. invadens genes: a putative rhomboid protease gene and a SHAQKY family Myb gene. The Myb gene is upregulated during oxidative stress and development, and its downregulation led, as predicted, to decreased viability under oxidative stress and decreased cyst formation. Thus, the RNAi trigger silencing method can be used to successfully investigate the molecular functions of genes inE. invadens Dissection of the molecular basis of Entamoeba stage conversion is now possible, representing an important technical advance for the system. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  7. The Luteovirus P4 Movement Protein Is a Suppressor of Systemic RNA Silencing

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    Adriana F. Fusaro

    2017-10-01

    Full Text Available The plant viral family Luteoviridae is divided into three genera: Luteovirus, Polerovirus and Enamovirus. Without assistance from another virus, members of the family are confined to the cells of the host plant’s vascular system. The first open reading frame (ORF of poleroviruses and enamoviruses encodes P0 proteins which act as silencing suppressor proteins (VSRs against the plant’s viral defense-mediating RNA silencing machinery. Luteoviruses, such as barley yellow dwarf virus-PAV (BYDV-PAV, however, have no P0 to carry out the VSR role, so we investigated whether other proteins or RNAs encoded by BYDV-PAV confer protection against the plant’s silencing machinery. Deep-sequencing of small RNAs from plants infected with BYDV-PAV revealed that the virus is subjected to RNA silencing in the phloem tissues and there was no evidence of protection afforded by a possible decoy effect of the highly abundant subgenomic RNA3. However, analysis of VSR activity among the BYDV-PAV ORFs revealed systemic silencing suppression by the P4 movement protein, and a similar, but weaker, activity by P6. The closely related BYDV-PAS P4, but not the polerovirus potato leafroll virus P4, also displayed systemic VSR activity. Both luteovirus and the polerovirus P4 proteins also showed transient, weak local silencing suppression. This suggests that systemic silencing suppression is the principal mechanism by which the luteoviruses BYDV-PAV and BYDV-PAS minimize the effects of the plant’s anti-viral defense.

  8. The Mutant KRAS Gene Up-regulates BCL-XL Protein via STAT3 to Confer Apoptosis Resistance That Is Reversed by BIM Protein Induction and BCL-XL Antagonism.

    Science.gov (United States)

    Zaanan, Aziz; Okamoto, Koichi; Kawakami, Hisato; Khazaie, Khashayarsha; Huang, Shengbing; Sinicrope, Frank A

    2015-09-25

    In colorectal cancers with oncogenic GTPase Kras (KRAS) mutations, inhibition of downstream MEK/ERK signaling has shown limited efficacy, in part because of failure to induce a robust apoptotic response. We studied the mechanism of apoptosis resistance in mutant KRAS cells and sought to enhance the efficacy of a KRAS-specific MEK/ERK inhibitor, GDC-0623. GDC-0623 was shown to potently up-regulate BIM expression to a greater extent versus other MEK inhibitors in isogenic KRAS HCT116 and mutant KRAS SW620 colon cancer cells. ERK silencing enhanced BIM up-regulation by GDC-0623 that was due to its loss of phosphorylation at Ser(69), confirmed by a BIM-EL phosphorylation-defective mutant (S69G) that increased protein stability and blocked BIM induction. Despite BIM and BIK induction, the isogenic KRAS mutant versus wild-type cells remained resistant to GDC-0623-induced apoptosis, in part because of up-regulation of BCL-XL. KRAS knockdown by a doxycycline-inducible shRNA attenuated BCL-XL expression. BCL-XL knockdown sensitized KRAS mutant cells to GDC-0623-mediated apoptosis, as did the BH3 mimetic ABT-263. GDC-0623 plus ABT-263 induced a synergistic apoptosis by a mechanism that includes release of BIM from its sequestration by BCL-XL. Furthermore, mutant KRAS activated p-STAT3 (Tyr(705)) in the absence of IL-6 secretion, and STAT3 knockdown reduced BCL-XL mRNA and protein expression. These data suggest that BCL-XL up-regulation by STAT3 contributes to mutant KRAS-mediated apoptosis resistance. Such resistance can be overcome by potent BIM induction and concurrent BCL-XL antagonism to enable a synergistic apoptotic response. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. ANTAGONISM OF A. VIRIDANS TO CONDITIONALLY - PATHOGENIC MICROFLORA OF THE NOSE AND OROPHARYNX OF CHILDREN WITH CARDIAC PATOLOGY

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    Stepansky D.O.

    2015-12-01

    Full Text Available Introduction. Search for harmless and simultaneously effective probiotics, which could be successfully used for treatment and prevention of infectious deseases, is currently important. A. viridans is of particular interest, as it is representative of the normal microflora of human with broad spectrum of antibacterial action. The use of this microorganism has a number of advantages: the absence of side effects on the body; high adhesive abilities; resistance to lysozyme in saliva; the ability of use in patients, sensitized to antibiotics and chemotherapeutic drugs; stimulation effects on the human immune system. Material and methods. The purpose of the study was to investigate the antagonism of A. viridans № 167 and autostrains of aerococcuses, isolated at patients, to conditionally - pathogenic microflora of the nose and oropharynx of children with cardiac patology. At the first stage of the study the microflora of the of the nose and oropharynx of 2 investigated categories was examined – 40 children 4-14 years with cardiac patology and 40 healthy children 4-5 years old. The second stage of work was to study the effect of A. viridans on the explored strains. Results and discussion. A. viridans manifests the antagonism to all studied strains of gram-positive and gram-negative microorganisms, except C. albisans. A. viridans antagonistic activity to staphylococci (10 + 3 mm and streptococci (10 + 2mm is at the approximately same level. It is interesting to compare the antagonism of aerococcuses to clinical isolates of S. pyogenes and similar strains from carriers (healthy children category. Impact of aerococcuses on P. mirabilis strain appeared at the highest level. Autosimbionts of A. viridans, isolated from healthy children, are more antagonistic to CPM strains, isolated from these children, than autostrains of A. viridans, isolated from children with with cardiac patology, and higher than the museum strain of A. viridans № 167 antagonism

  10. C. elegans RNA-dependent RNA polymerases rrf-1 and ego-1 silence Drosophila transgenes by differing mechanisms.

    Science.gov (United States)

    Duan, Guowen; Saint, Robert B; Helliwell, Chris A; Behm, Carolyn A; Wang, Ming-Bo; Waterhouse, Peter M; Gordon, Karl H J

    2013-04-01

    Drosophila possesses the core gene silencing machinery but, like all insects, lacks the canonical RNA-dependent RNA polymerases (RdRps) that in C. elegans either trigger or enhance two major small RNA-dependent gene silencing pathways. Introduction of two different nematode RdRps into Drosophila showed them to be functional, resulting in differing silencing activities. While RRF-1 enhanced transitive dsRNA-dependent silencing, EGO-1 triggered dsRNA-independent silencing, specifically of transgenes. The strain w; da-Gal4; UAST-ego-1, constitutively expressing ego-1, is capable of silencing transgene including dsRNA hairpin upon a single cross, which created a powerful tool for research in Drosophila. In C. elegans, EGO-1 is involved in transcriptional gene silencing (TGS) of chromosome regions that are unpaired during meiosis. There was no opportunity for meiotic interactions involving EGO-1 in Drosophila that would explain the observed transgene silencing. Transgene DNA is, however, unpaired during the pairing of chromosomes in embryonic mitosis that is an unusual characteristic of Diptera, suggesting that in Drosophila, EGO-1 triggers transcriptional silencing of unpaired DNA during embryonic mitosis.

  11. The VP3 factor from viruses of Birnaviridae family suppresses RNA silencing by binding both long and small RNA duplexes.

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    Adrian Valli

    Full Text Available RNA silencing is directly involved in antiviral defense in a wide variety of eukaryotic organisms, including plants, fungi, invertebrates, and presumably vertebrate animals. The study of RNA silencing-mediated antiviral defences in vertebrates is hampered by the overlap with other antiviral mechanisms; thus, heterologous systems are often used to study the interplay between RNA silencing and vertebrate-infecting viruses. In this report we show that the VP3 protein of the avian birnavirus Infectious bursal disease virus (IBDV displays, in addition to its capacity to bind long double-stranded RNA, the ability to interact with double-stranded small RNA molecules. We also demonstrate that IBDV VP3 prevents the silencing mediated degradation of a reporter mRNA, and that this silencing suppression activity depends on its RNA binding ability. Furthermore, we find that the anti-silencing activity of IBDV VP3 is shared with the homologous proteins expressed by both insect- and fish-infecting birnaviruses. Finally, we show that IBDV VP3 can functionally replace the well-characterized HCPro silencing suppressor of Plum pox virus, a potyvirus that is unable to infect plants in the absence of an active silencing suppressor. Altogether, our results support the idea that VP3 protects the viral genome from host sentinels, including those of the RNA silencing machinery.

  12. The VP3 factor from viruses of Birnaviridae family suppresses RNA silencing by binding both long and small RNA duplexes.

    Science.gov (United States)

    Valli, Adrian; Busnadiego, Idoia; Maliogka, Varvara; Ferrero, Diego; Castón, José R; Rodríguez, José Francisco; García, Juan Antonio

    2012-01-01

    RNA silencing is directly involved in antiviral defense in a wide variety of eukaryotic organisms, including plants, fungi, invertebrates, and presumably vertebrate animals. The study of RNA silencing-mediated antiviral defences in vertebrates is hampered by the overlap with other antiviral mechanisms; thus, heterologous systems are often used to study the interplay between RNA silencing and vertebrate-infecting viruses. In this report we show that the VP3 protein of the avian birnavirus Infectious bursal disease virus (IBDV) displays, in addition to its capacity to bind long double-stranded RNA, the ability to interact with double-stranded small RNA molecules. We also demonstrate that IBDV VP3 prevents the silencing mediated degradation of a reporter mRNA, and that this silencing suppression activity depends on its RNA binding ability. Furthermore, we find that the anti-silencing activity of IBDV VP3 is shared with the homologous proteins expressed by both insect- and fish-infecting birnaviruses. Finally, we show that IBDV VP3 can functionally replace the well-characterized HCPro silencing suppressor of Plum pox virus, a potyvirus that is unable to infect plants in the absence of an active silencing suppressor. Altogether, our results support the idea that VP3 protects the viral genome from host sentinels, including those of the RNA silencing machinery.

  13. Nicotinamide clearance by Pnc1 directly regulates Sir2-mediated silencing and longevity.

    Science.gov (United States)

    Gallo, Christopher M; Smith, Daniel L; Smith, Jeffrey S

    2004-02-01

    The Saccharomyces cerevisiae Sir2 protein is an NAD(+)-dependent histone deacetylase (HDAC) that functions in transcriptional silencing and longevity. The NAD(+) salvage pathway protein, Npt1, regulates Sir2-mediated processes by maintaining a sufficiently high intracellular NAD(+) concentration. However, another NAD(+) salvage pathway component, Pnc1, modulates silencing independently of the NAD(+) concentration. Nicotinamide (NAM) is a by-product of the Sir2 deacetylase reaction and is a natural Sir2 inhibitor. Pnc1 is a nicotinamidase that converts NAM to nicotinic acid. Here we show that recombinant Pnc1 stimulates Sir2 HDAC activity in vitro by preventing the accumulation of NAM produced by Sir2. In vivo, telomeric, rDNA, and HM silencing are differentially sensitive to inhibition by NAM. Furthermore, PNC1 overexpression suppresses the inhibitory effect of exogenously added NAM on silencing, life span, and Hst1-mediated transcriptional repression. Finally, we show that stress suppresses the inhibitory effect of NAM through the induction of PNC1 expression. Pnc1, therefore, positively regulates Sir2-mediated silencing and longevity by preventing the accumulation of intracellular NAM during times of stress.

  14. [Silence pact from the perspective of caretakers of palliative care patients].

    Science.gov (United States)

    Cejudo López, Ángela; López López, Begoña; Duarte Rodríguez, Miguel; Crespo Serván, María Pilar; Coronado Illescas, Concepción; de la Fuente Rodríguez, Carlota

    2015-01-01

    To determine why terminally-ill patients, family caregivers and health care providers make a pact of silence about the terminal status of the patient, and to identify the attitudes, experiences and opinions of family caregivers concerning the conspiracy of silence in palliative care. A qualitative phenomenological study based on an interpretive analysis, conducted in Primary Health Care, Seville, Spain. Study dimensions: knowledge of the diagnosis and prognosis of the condition; disclosure of information; reaction to information received, feelings and approach to death; information disclosed to the patient and reasons behind partial disclosure; communication between patients, families, and health care providers. Family caregivers of patients on palliative care suspicious about a pact of silence. Family caregivers hamper professional-patient communication; use of deceit to conceal the truth; suspicion that the patient knows the truth; the clinician conceals the truth; paternalist attitudes; feelings of sadness, grief, resignation, acceptance of the disease. The pact of silence has negative effects on coping with death, quality of life in the last days of life, and mourning. Communication between patients, health care providers, and families should be improved to prevent the pact of silence, and help patients cope with death. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

  15. Inheritable Silencing of Endogenous Genes by Hit-and-Run Targeted Epigenetic Editing.

    Science.gov (United States)

    Amabile, Angelo; Migliara, Alessandro; Capasso, Paola; Biffi, Mauro; Cittaro, Davide; Naldini, Luigi; Lombardo, Angelo

    2016-09-22

    Gene silencing is instrumental to interrogate gene function and holds promise for therapeutic applications. Here, we repurpose the endogenous retroviruses' silencing machinery of embryonic stem cells to stably silence three highly expressed genes in somatic cells by epigenetics. This was achieved by transiently expressing combinations of engineered transcriptional repressors that bind to and synergize at the target locus to instruct repressive histone marks and de novo DNA methylation, thus ensuring long-term memory of the repressive epigenetic state. Silencing was highly specific, as shown by genome-wide analyses, sharply confined to the targeted locus without spreading to nearby genes, resistant to activation induced by cytokine stimulation, and relieved only by targeted DNA demethylation. We demonstrate the portability of this technology by multiplex gene silencing, adopting different DNA binding platforms and interrogating thousands of genomic loci in different cell types, including primary T lymphocytes. Targeted epigenome editing might have broad application in research and medicine. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  16. Transcriptionally Silenced Transgenes in Maize Are Activated by Three Mutations Defective in Paramutation

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    McGinnis, Karen M.; Springer, Catherine; Lin, Yan; Carey, Charles C.; Chandler, Vicki

    2006-01-01

    Plants with mutations in one of three maize genes, mop1, rmr1, and rmr2, are defective in paramutation, an allele-specific interaction that leads to meiotically heritable chromatin changes. Experiments reported here demonstrate that these genes are required to maintain the transcriptional silencing of two different transgenes, suggesting that paramutation and transcriptional silencing of transgenes share mechanisms. We hypothesize that the transgenes are silenced through an RNA-directed chromatin mechanism, because mop1 encodes an RNA-dependent RNA polymerase. In all the mutants, DNA methylation was reduced in the active transgenes relative to the silent transgenes at all of the CNG sites monitored within the transgene promoter. However, asymmetrical methylation persisted at one site within the reactivated transgene in the rmr1-1 mutant. With that one mutant, rmr1-1, the transgene was efficiently resilenced upon outcrossing to reintroduce the wild-type protein. In contrast, with the mop1-1 and rmr2-1 mutants, the transgene remained active in a subset of progeny even after the wild-type proteins were reintroduced by outcrossing. Interestingly, this immunity to silencing increased as the generations progressed, consistent with a heritable chromatin state being formed at the transgene in plants carrying the mop1-1 and rmr2-1 mutations that becomes more resistant to silencing in subsequent generations. PMID:16702420

  17. Identification of Novel Fibrosis Modifiers by In Vivo siRNA Silencing

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    Elisabeth H. Vollmann

    2017-06-01

    Full Text Available Fibrotic diseases contribute to 45% of deaths in the industrialized world, and therefore a better understanding of the pathophysiological mechanisms underlying tissue fibrosis is sorely needed. We aimed to identify novel modifiers of tissue fibrosis expressed by myofibroblasts and their progenitors in their disease microenvironment through RNA silencing in vivo. We leveraged novel biology, targeting genes upregulated during liver and kidney fibrosis in this cell lineage, and employed small interfering RNA (siRNA-formulated lipid nanoparticles technology to silence these genes in carbon-tetrachloride-induced liver fibrosis in mice. We identified five genes, Egr2, Atp1a2, Fkbp10, Fstl1, and Has2, which modified fibrogenesis based on their silencing, resulting in reduced Col1a1 mRNA levels and collagen accumulation in the liver. These genes fell into different groups based on the effects of their silencing on a transcriptional mini-array and histological outcomes. Silencing of Egr2 had the broadest effects in vivo and also reduced fibrogenic gene expression in a human fibroblast cell line. Prior to our study, Egr2, Atp1a2, and Fkbp10 had not been functionally validated in fibrosis in vivo. Thus, our results provide a major advance over the existing knowledge of fibrogenic pathways. Our study is the first example of a targeted siRNA assay to identify novel fibrosis modifiers in vivo.

  18. Lack of sex chromosome specific meiotic silencing in platypus reveals origin of MSCI in therian mammals.

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    Daish, Tasman J; Casey, Aaron E; Grutzner, Frank

    2015-12-10

    In therian mammals heteromorphic sex chromosomes are subject to meiotic sex chromosome inactivation (MSCI) during meiotic prophase I while the autosomes maintain transcriptional activity. The evolution of this sex chromosome silencing is thought to result in retroposition of genes required in spermatogenesis from the sex chromosomes to autosomes. In birds sex chromosome specific silencing appears to be absent and global transcriptional reductions occur through pachytene and sex chromosome-derived autosomal retrogenes are lacking. Egg laying monotremes are the most basal mammalian lineage, feature a complex and highly differentiated XY sex chromosome system with homology to the avian sex chromosomes, and also lack autosomal retrogenes. In order to delineate the point of origin of sex chromosome specific silencing in mammals we investigated whether MSCI exists in platypus. Our results show that platypus sex chromosomes display only partial or transient colocalisation with a repressive histone variant linked to therian sex chromosome silencing and surprisingly lack a hallmark MSCI epigenetic signature present in other mammals. Remarkably, platypus instead feature an avian like period of general low level transcription through prophase I with the sex chromosomes and the future mammalian X maintaining association with a nucleolus-like structure. Our work demonstrates for the first time that in mammals meiotic silencing of sex chromosomes evolved after the divergence of monotremes presumably as a result of the differentiation of the therian XY sex chromosomes. We provide a novel evolutionary scenario on how the future therian X chromosome commenced the trajectory toward MSCI.

  19. A conversation analysis of the function of silence in writing conferences

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    Milad Mirzaee

    2016-07-01

    Full Text Available One of the recent issues in English as a Second/Foreign Language (ESL/EFL writing instruction has been the quest for a more effective way to give feedback to L2 learners’ writing drafts. Although teacher- learner writing conferences have been increasingly used for providing ample opportunity for negotiating revisions, relatively little attention has been given to actual teacher-learner conversation. Drawing on sociocultural theory, which holds that all cognitive developments are results of ‘social interactions’, and drawing on conversation analysis as an analytical tool, this study attempts to explore the different functions of ‘silence’ in writing conferences during teacher-learner conversation. The data comes from transcripts of six 1-hour writing conferences video-recorded in a graduate program with 7 candidates in Iran. During the writing conferences, learners’ drafts were discussed. Findings of the study demonstrated that teacher’s silence can play a key role in the management of turns in writing conferences, thereby providing the parties with various opportunities for accomplishing intersubjectivity: the teacher used silence to rethink the information provided during writing conferences, and the learner exploited silence to revise the writing draft. The current study, reporting a range of functions of silence in writing conferences, offers an extension to the existing literature and draws language teachers’, specifically writing instructors’, attention to different functions of silence in writing conferences.

  20. Breaking an epigenetic chromatin switch: curious features of hysteresis in Saccharomyces cerevisiae telomeric silencing.

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    Vijayalakshmi H Nagaraj

    Full Text Available In addition to gene network switches, local epigenetic modifications to DNA and histones play an important role in all-or-none cellular decision-making. Here, we study the dynamical design of a well-characterized epigenetic chromatin switch: the yeast SIR system, in order to understand the origin of the stability of epigenetic states. We study hysteresis in this system by perturbing it with a histone deacetylase inhibitor. We find that SIR silencing has many characteristics of a non-linear bistable system, as observed in conventional genetic switches, which are based on activities of a few promoters affecting each other through the abundance of their gene products. Quite remarkably, our experiments in yeast telomeric silencing show a very distinctive pattern when it comes to the transition from bistability to monostability. In particular, the loss of the stable silenced state, upon increasing the inhibitor concentration, does not seem to show the expected saddle node behavior, instead looking like a supercritical pitchfork bifurcation. In other words, the 'off' state merges with the 'on' state at a threshold concentration leading to a single state, as opposed to the two states remaining distinct up to the threshold and exhibiting a discontinuous jump from the 'off' to the 'on' state. We argue that this is an inevitable consequence of silenced and active regions coexisting with dynamic domain boundaries. The experimental observations in our study therefore have broad implications for the understanding of chromatin silencing in yeast and beyond.

  1. Potential of Metal Fibre Felts as Passive Absorbers in Absorption Silencers

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    Björn Hinze

    2013-03-01

    Full Text Available The growing noise exposure of residents, due to a rising number of flights, causes significant impacts on physical health. Therefore it is necessary to reduce the noise emission of aircrafts. During take-off, the noise generated by the jet engines is dominating. One way to lower the noise emission of jet engines is to build an absorption silencer by using porous liners. Because of the high thermic and corrosive attacks as well as high fatigue loads, conventional absorbers cannot be used. A promising material is sintered metal fibre felts. This study investigates the suitability of metal fibre felts for the use as absorption material in silencers. The influences of pore morphology, absorption coefficient, determined with perpendicular sound incidence, as well as geometric parameters of the silencer to the damping are identified. To characterise the material, the parameters fibre diameter, porosity and thickness are determined using three-dimensional computer tomography images. The damping potential of absorption silencers is measured using an impedance tube, which was modified for transmission measurements. The essential parameter to describe the acoustic characteristics of porous materials is the flow resistivity. It depends on the size, shape and number of open pores in the material. Finally a connection between pore morphology, flow resistivity of the metal fibre felts and damping potential of the absorption silencer is given.

  2. Disulfide bond-conjugated dual PEGylated siRNAs for prolonged multiple gene silencing.

    Science.gov (United States)

    Liao, Zi-Xian; Hsiao, Chun-Wen; Ho, Yi-Cheng; Chen, Hsin-Lung; Sung, Hsing-Wen

    2013-09-01

    Many human diseases carry at least two independent gene mutations, further exacerbating clinical disorders. In this work, disulfide bond-conjugated dual PEGylated siRNAs were synthesized, capable of specifically targeting and silencing two genes simultaneously. To achieve efficient delivery, the conjugated siRNAs were formulated with the cationic chitosan together with an anionic polymer, poly(γ-glutamic acid) (γPGA), to form a ternary complex. Experimental results indicate that the incorporated γPGA could significantly enhance their intracellular delivery efficiency, allowing for reduction of the disulfide bond-conjugated PEGylated siRNAs delivered to the PEGylated siRNAs in the reductive cytoplasmic environment. The PEGylated siRNAs could more significantly increase their enzymatic tolerability, effectively silence multiple genes, and prolong the duration of their gene silencing capability than the unmodified siRNAs could. Silencing of different genes simultaneously significantly contributes to the efforts to treat multiple gene disorders, and prolonged duration of gene silencing can reduce the need for frequent administrations. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Klotho gene silencing promotes pathology in the mdx mouse model of Duchenne muscular dystrophy

    Science.gov (United States)

    Wehling-Henricks, Michelle; Li, Zhenzhi; Lindsey, Catherine; Wang, Ying; Welc, Steven S.; Ramos, Julian N.; Khanlou, Négar; Kuro-o, Makoto; Tidball, James G.

    2016-01-01

    Duchenne muscular dystrophy (DMD) is a lethal muscle disease involving progressive loss of muscle regenerative capacity and increased fibrosis. We tested whether epigenetic silencing of the klotho gene occurs in the mdx mouse model of DMD and whether klotho silencing is an important feature of the disease. Our findings show that klotho undergoes muscle-specific silencing at the acute onset of mdx pathology. Klotho experiences increased methylation of CpG sites in its promoter region, which is associated with gene silencing, and increases in a repressive histone mark, H3K9me2. Expression of a klotho transgene in mdx mice restored their longevity, reduced muscle wasting, improved function and greatly increased the pool of muscle-resident stem cells required for regeneration. Reductions of fibrosis in late, progressive stages of the mdx pathology achieved by transgene expression were paralleled by reduced expression of Wnt target genes (axin-2), transforming growth factor-beta (TGF-β1) and collagens types 1 and 3, indicating that Klotho inhibition of the profibrotic Wnt/TGFβ axis underlies its anti-fibrotic effect in aging, dystrophic muscle. Thus, epigenetic silencing of klotho during muscular dystrophy contributes substantially to lost regenerative capacity and increased fibrosis of dystrophic muscle during late progressive stages of the disease. PMID:27154199

  4. Membrane-associated transcription factor peptidase, site-2 protease, antagonizes ABA signaling in Arabidopsis.

    Science.gov (United States)

    Zhou, Shun-Fan; Sun, Le; Valdés, Ana Elisa; Engström, Peter; Song, Ze-Ting; Lu, Sun-Jie; Liu, Jian-Xiang

    2015-10-01

    Abscisic acid plays important roles in maintaining seed dormancy while gibberellins (GA) and other phytohormones antagonize ABA to promote germination. However, how ABA signaling is desensitized during the transition from dormancy to germination is still poorly understood. We functionally characterized the role of membrane-associated transcription factor peptidase, site-2 protease (S2P), in ABA signaling during seed germination in Arabidopsis. Genetic analysis showed that loss-of-function of S2P conferred high ABA sensitivity during seed germination, and expression of the activated form of membrane-associated transcription factor bZIP17, in which the transmembrane domain and endoplasmic reticulum (ER) lumen-facing C-terminus were deleted, in the S2P mutant rescued its ABA-sensitive phenotype. MYC and green fluorescent protein (GFP)-tagged bZIP17 were processed and translocated from the ER to the nucleus in response to ABA treatment. Furthermore, genes encoding negative regulators of ABA signaling, such as the transcription factor ATHB7 and its target genes HAB1, HAB2, HAI1 and AHG3, were up-regulated in seeds of the wild-type upon ABA treatment; this up-regulation was impaired in seeds of S2P mutants. Our results suggest that S2P desensitizes ABA signaling during seed germination through regulating the activation of the membrane-associated transcription factor bZIP17 and therefore controlling the expression level of genes encoding negative regulators of ABA signaling. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  5. ROS inhibitor N-acetyl-L-cysteine antagonizes the activity of proteasome inhibitors.

    Science.gov (United States)

    Halasi, Marianna; Wang, Ming; Chavan, Tanmay S; Gaponenko, Vadim; Hay, Nissim; Gartel, Andrei L

    2013-09-01

    NAC (N-acetyl-L-cysteine) is commonly used to identify and test ROS (reactive oxygen species) inducers, and to inhibit ROS. In the present study, we identified inhibition of proteasome inhibitors as a novel activity of NAC. Both NAC and catalase, another known scavenger of ROS, similarly inhibited ROS levels and apoptosis associated with H₂O₂. However, only NAC, and not catalase or another ROS scavenger Trolox, was able to prevent effects linked to proteasome inhibition, such as protein stabilization, apoptosis and accumulation of ubiquitin conjugates. These observations suggest that NAC has a dual activity as an inhibitor of ROS and proteasome inhibitors. Recently, NAC was used as a ROS inhibitor to functionally characterize a novel anticancer compound, piperlongumine, leading to its description as a ROS inducer. In contrast, our own experiments showed that this compound depicts features of proteasome inhibitors including suppression of FOXM1 (Forkhead box protein M1), stabilization of cellular proteins, induction of ROS-independent apoptosis and enhanced accumulation of ubiquitin conjugates. In addition, NAC, but not catalase or Trolox, interfered with the activity of piperlongumine, further supporting that piperlongumine is a proteasome inhibitor. Most importantly, we showed that NAC, but not other ROS scavengers, directly binds to proteasome inhibitors. To our knowledge, NAC is the first known compound that directly interacts with and antagonizes the activity of proteasome inhibitors. Taken together, the findings of the present study suggest that, as a result of the dual nature of NAC, data interpretation might not be straightforward when NAC is utilized as an antioxidant to demonstrate ROS involvement in drug-induced apoptosis.

  6. Substance P Receptor Antagonism: A Potential Novel Treatment Option for Viral-Myocarditis

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    Prema Robinson

    2015-01-01

    Full Text Available Viral-myocarditis is an important cause of heart failure for which no specific treatment is available. We previously showed the neuropeptide substance P (SP is associated with the pathogenesis of murine myocarditis caused by encephalomyocarditis virus (EMCV. The current studies determined if pharmacological inhibition of SP-signaling via its high affinity receptor, NK1R and downstream G-protein, Ras homolog gene family, member-A (RhoA, will be beneficial in viral-myocarditis. Aprepitant (1.2 mg/kg, a SP-receptor antagonist, or fasudil (10 mg/kg, a RhoA inhibitor, or saline control was administered daily to mice orally for 3 days, prior to, or 5 days following, intraperitoneal infection with and without 50 PFU of EMCV, following which disease assessment studies, including echocardiogram and cardiac Doppler were performed in day 14 after infection. Pretreatment and posttreatment with aprepitant significantly reduced mortality, heart and cardiomyocyte size, and cardiac viral RNA levels (P<0.05 all, ANOVA. Only aprepitant pretreatment improved heart functions; it significantly decreased end systolic diameter, improved fractional shortening, and increased peak aortic flow velocity (P<0.05 all, ANOVA. Pre- or posttreatment with fasudil did not significantly impact disease manifestations. These findings indicate that SP contributes to cardiac-remodeling and dysfunction following ECMV infection via its high affinity receptor, but not through the Rho-A pathway. These studies suggest that SP-receptor antagonism may be a novel therapeutic-option for patients with viral-myocarditis.

  7. Metabotropic glutamate 5 receptor antagonism is associated with antidepressant-like effects in mice.

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    Li, Xia; Need, Anne B; Baez, Melvyn; Witkin, Jeffrey M

    2006-10-01

    Antidepressant-like effects of metabotropic glutamate (mGlu)5 receptor antagonists have been reported previously. We now provide definitive identification of mGlu5 receptors as a target for these effects through the combined use of selective antagonists and mice with targeted deletion of the mGlu5 protein. In these experiments, the mGlu5 receptor antagonists 2-methyl-6-(phenylethynyl)-pyridine (MPEP) and the more selective and metabolically stable analog 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]-pyridine (MTEP) decreased immobility in the mouse forced swim test, a test predictive of antidepressant efficacy in humans. mGlu5 receptor knockout mice had a phenotype in the forced swim test that was congruent with the effects of receptor blockade; mGlu5 receptor knockout mice were significantly less immobile than their wild-type counterparts. Consistent with mGlu5 receptor mediation of the antidepressant-like effects of MPEP, the effects of MPEP were not observed in mGlu5 receptor knockout mice, whereas comparable effects of the tricyclic antidepressant imiprimine remained active in the mutant mice. MPEP and imiprimine resulted in a synergistic antidepressant-like effect in the forced swim test. The drug interaction was not likely because of increased levels of drugs in the brain, suggesting a pharmacodynamic interaction of mGlu5 and monoaminergic systems in this effect. Thus, the present findings substantiate the hypothesis that mGlu5 receptor antagonism is associated with antidepressant-like effects. This mechanism may not only provide a novel approach to the therapeutic management of depressive disorders but also may be useful in the augmentation of effects of traditional antidepressant agents.

  8. MafB antagonizes phenotypic alteration induced by GM-CSF in microglia

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    Koshida, Ryusuke, E-mail: rkoshida-myz@umin.ac.jp; Oishi, Hisashi, E-mail: hoishi@md.tsukuba.ac.jp; Hamada, Michito; Takahashi, Satoru

    2015-07-17

    Microglia are tissue-resident macrophages which are distributed throughout the central nervous system (CNS). Recent studies suggest that microglia are a unique myeloid population distinct from peripheral macrophages in terms of origin and gene expression signature. Granulocyte-macrophage colony-stimulating factor (GM-CSF), a pleiotropic cytokine regulating myeloid development, has been shown to stimulate proliferation and alter phenotype of microglia in vitro. However, how its signaling is modulated in microglia is poorly characterized. MafB, a bZip transcriptional factor, is highly expressed in monocyte-macrophage lineage cells including microglia, although its role in microglia is largely unknown. We investigated the crosstalk between GM-CSF signaling and MafB by analyzing primary microglia. We found that Mafb-deficient microglia grew more rapidly than wild-type microglia in response to GM-CSF. Moreover, the expression of genes associated with microglial differentiation was more downregulated in Mafb-deficient microglia cultured with GM-CSF. Notably, such differences between the genotypes were not observed in the presence of M-CSF. In addition, we found that Mafb-deficient microglia cultured with GM-CSF barely extended their membrane protrusions, probably due to abnormal activation of RhoA, a key regulator of cytoskeletal remodeling. Altogether, our study reveals that MafB is a negative regulator of GM-CSF signaling in microglia. These findings could provide new insight into the modulation of cytokine signaling by transcription factors in microglia. - Highlights: • GM-CSF alters the phenotype of microglia in vitro more potently than M-CSF. • Transcription factor MafB antagonizes the effect of GM-CSF on microglia in vitro. • MafB deficiency leads to RhoA activation in microglia in response to GM-CSF. • We show for the first time the function of MafB in microglia.

  9. The therapeutic promise of ATP antagonism at P2X3 receptors in respiratory & urological disorders

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    Anthony eFord

    2013-12-01

    Full Text Available A sensory role for ATP was proposed long before general acceptance of its extracellular role. ATP activates & sensitizes signal transmission at multiple sites along the sensory axis, across multiple synapses. P2X & P2Y receptors mediate ATP modulation of sensory pathways & participate in dysregulation, where ATP action directly on primary afferent neurons (PANs, linking receptive field to CNS, has received much attention. Many PANs, especially C-fibers, are activated by ATP, via P2X3-containing trimers. P2X3 knock-out mice & knock-down in rats led to reduced nocifensive activity & visceral reflexes, suggesting that antagonism may offer benefit in sensory disorders. Recently, drug-like P2X3 antagonists, active in a many inflammatory & visceral pain models, have emerged. Significantly, these compounds have no overt CNS action & are inactive versus acute nociception. Selectively targeting ATP sensitization of PANs may lead to therapies that block inappropriate chronic signals at their source, decreasing drivers of peripheral & central wind-up, yet leaving defensive nociceptive and brain functions unperturbed. This article reviews this evidence, focusing on how ATP sensitization of PANs in visceral hollow organs primes them to chronic discomfort, irritation & pain (symptoms as well as exacerbated autonomic reflexes (signs, & how the use of isolated organ-nerve preparations has revealed this mechanism. Urinary & airways systems share many features: dependence on continuous afferent traffic to brainstem centers to coordinate efferent autonomic outflow; loss of descending inhibitory influence in functional & sensory disorders; dependence on ATP in mediating sensory responses to diverse mechanical and chemical stimuli; a mechanistically overlapping array of existing medicines for pathological conditions. These similarities may also play out in terms of future treatment of signs & symptoms, in the potential for benefit of P2X3 antagonists.

  10. Separating the Anti-Inflammatory and Diabetogenic Effects of Glucocorticoids Through LXRβ Antagonism.

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    Patel, Rucha; Magomedova, Lilia; Tsai, Ricky; Angers, Stéphane; Orellana, Arturo; Cummins, Carolyn L

    2017-04-01

    Synthetic glucocorticoids (GCs), including dexamethasone (DEX), are powerful anti-inflammatory drugs. Long-term use of GCs, however, can result in metabolic side effects such as hyperglycemia, hepatosteatosis, and insulin resistance. The GC receptor (GR) and liver X receptors (LXRα and LXRβ) regulate overlapping genes involved in gluconeogenesis and inflammation. We have previously shown that Lxrβ-/- mice are resistant to the diabetogenic effects of DEX but still sensitive to its immunosuppressive actions. To determine whether this finding could be exploited for therapeutic intervention, we treated mice with GSK2033, a pan-LXR antagonist, alone or combined with DEX. GSK2033 suppressed GC-induced gluconeogenic gene expression without affecting immune-responsive GR target genes. The suppressive effect of GSK2033 on DEX-induced gluconeogenic genes was specific to LXRβ, was liver cell autonomous, and occurred in a target gene-specific manner. Compared with DEX treatment alone, the coadministration of GSK2033 with DEX decreased the recruitment of GR and its accessory factors MED1 and C/EBPβ to the phosphoenolpyruvate carboxykinase promoter. However, GSK2033 had no effect on DEX-mediated suppression of inflammatory genes expressed in the liver or in mouse primary macrophages stimulated with lipopolysaccharides. In conclusion, our study provides evidence that the gluconeogenic and immunosuppressive actions of GR activation can be mechanistically dissociated by pharmacological antagonism of LXRβ. Treatment with an LXRβ antagonist could allow the safer use of existing GC drugs in patients requiring chronic dosing of anti-inflammatory agents for the treatment of diseases such as rheumatoid arthritis and inflammatory bowel disease. Copyright © 2017 Endocrine Society.

  11. Cerebral, spinal and peripheral inhibition of gastrointestinal transit by PI017: differential antagonism by naloxonazine

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    Williams, C.L.; Heyman, J.S.; Porreca, F.; Burks, T.F.

    1986-03-05

    The authors were interested in characterizing the relative importance of central (cerebral, spinal) and peripheral opioid receptors in inhibition of gastrointestinal transit. The mu-receptor selective agonist, (NMePhe/sup 3/,D-Pro/sup 4/)morphiceptin (PL017), was evaluated for its effectiveness in slowing gastrointestinal transit after subcutaneous, intracerebroventricular (i.c.v.) or intrathecal (i.th.) administration when given alone or after pretreatment with naloxonazine, an irreversible mu/sub 1/ selective opioid receptor antagonist. Male, ICR mice (20-25 g) were pretreated with saline, naloxone or naloxonazine (35 mg/kg, s.c.) 25 hr prior to testing. Gastrointestinal transit was evaluated in previously fasted (18 hr) mice by oral administration of a liquid radiolabelled marker (Na/sub 2//sup 51/CrO/sub 4/). I.th. PL017 (100-1000 ng) was effective in slowing transit, but was essentially insensitive to naloxone or naloxonazine pretreatment. PL017 produced a dose-related inhibition of transit when given by either the i.c.v. (100-1000 ng) or s.c.(1-10 mg/kg) route; this effect was not sensitive to naloxone pretreatment but was antagonized by naloxonazine. These results indicate that the opioid receptors mediating gastrointestinal transit in the brain and periphery may be mu/sub 1/. In contrast, the insensitivity to naloxonazine suggests that the gastrointestinal effects of PL017 in the spinal cord may be the result of activation of mu/sub 2/ or possibly delta opioid receptors.

  12. Zika Virus Antagonizes Type I Interferon Responses during Infection of Human Dendritic Cells.

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    James R Bowen

    2017-02-01

    Full Text Available Zika virus (ZIKV is an emerging mosquito-borne flavivirus that is causally linked to severe neonatal birth defects, including microcephaly, and is associated with Guillain-Barre syndrome in adults. Dendritic cells (DCs are an important cell type during infection by multiple mosquito-borne flaviviruses, including dengue virus, West Nile virus, Japanese encephalitis virus, and yellow fever virus. Despite this, the interplay between ZIKV and DCs remains poorly defined. Here, we found human DCs supported productive infection by a contemporary Puerto Rican isolate with considerable variability in viral replication, but not viral binding, between DCs from different donors. Historic isolates from Africa and Asia also infected DCs with distinct viral replication kinetics between strains. African lineage viruses displayed more rapid replication kinetics and infection magnitude as compared to Asian lineage viruses, and uniquely induced cell death. Infection of DCs with both contemporary and historic ZIKV isolates led to minimal up-regulation of T cell co-stimulatory and MHC molecules, along with limited secretion of inflammatory cytokines. Inhibition of type I interferon (IFN protein translation was observed during ZIKV infection, despite strong induction at the RNA transcript level and up-regulation of other host antiviral proteins. Treatment of human DCs with RIG-I agonist potently restricted ZIKV replication, while type I IFN had only modest effects. Mechanistically, we found all strains of ZIKV antagonized type I IFN-mediated phosphorylation of STAT1 and STAT2. Combined, our findings show that ZIKV subverts DC immunogenicity during infection, in part through evasion of type I IFN responses, but that the RLR signaling pathway is still capable of inducing an antiviral state, and therefore may serve as an antiviral therapeutic target.

  13. Antagonism of CD11b with neutrophil inhibitory factor (NIF) inhibits vascular lesions in diabetic retinopathy.

    Science.gov (United States)

    Veenstra, Alexander A; Tang, Jie; Kern, Timothy S

    2013-01-01

    Leukocytes and proteins that govern leukocyte adhesion to endothelial cells play a causal role in retinal abnormalities characteristic of the early stages of diabetic retinopathy, including diabetes-induced degeneration of retinal capillaries. Leukocyte integrin αmβ2 (CD11b/CD18, MAC1), a protein mediating adhesion, has been shown to mediate damage to endothelial cells by activated leukocytes in vitro. We hypothesized that Neutrophil Inhibitory Factor (NIF), a selective antagonist of integrin αmβ2, would inhibit the diabetes-induced degeneration of retinal capillaries by inhibiting the excessive interaction between leukocytes and retinal endothelial cells in diabetes. Wild type animals and transgenic animals expressing NIF were made diabetic with streptozotocin and assessed for diabetes-induced retinal vascular abnormalities and leukocyte activation. To assess if the leukocyte blocking therapy compromised the immune system, animals were challenged with bacteria. Retinal superoxide production, leukostasis and leukocyte superoxide production were increased in wild type mice diabetic for 10 weeks, as was the ability of leukocytes isolated from diabetic animals to kill retinal endothelial cells in vitro. Retinal capillary degeneration was significantly increased in wild type mice diabetic 40 weeks. In contrast, mice expressing NIF did not develop any of these abnormalities, with the exception that non-diabetic and diabetic mice expressing NIF generated greater amounts of superoxide than did similar mice not expressing NIF. Importantly, NIF did not significantly impair the ability of mice to clear an opportunistic bacterial challenge, suggesting that NIF did not compromise immune surveillance. We conclude that antagonism of CD11b (integrin αmβ2) by NIF is sufficient to inhibit early stages of diabetic retinopathy, while not compromising the basic immune response.

  14. Antagonism of CD11b with neutrophil inhibitory factor (NIF inhibits vascular lesions in diabetic retinopathy.

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    Alexander A Veenstra

    Full Text Available Leukocytes and proteins that govern leukocyte adhesion to endothelial cells play a causal role in retinal abnormalities characteristic of the early stages of diabetic retinopathy, including diabetes-induced degeneration of retinal capillaries. Leukocyte integrin αmβ2 (CD11b/CD18, MAC1, a protein mediating adhesion, has been shown to mediate damage to endothelial cells by activated leukocytes in vitro. We hypothesized that Neutrophil Inhibitory Factor (NIF, a selective antagonist of integrin αmβ2, would inhibit the diabetes-induced degeneration of retinal capillaries by inhibiting the excessive interaction between leukocytes and retinal endothelial cells in diabetes. Wild type animals and transgenic animals expressing NIF were made diabetic with streptozotocin and assessed for diabetes-induced retinal vascular abnormalities and leukocyte activation. To assess if the leukocyte blocking therapy compromised the immune system, animals were challenged with bacteria. Retinal superoxide production, leukostasis and leukocyte superoxide production were increased in wild type mice diabetic for 10 weeks, as was the ability of leukocytes isolated from diabetic animals to kill retinal endothelial cells in vitro. Retinal capillary degeneration was significantly increased in wild type mice diabetic 40 weeks. In contrast, mice expressing NIF did not develop any of these abnormalities, with the exception that non-diabetic and diabetic mice expressing NIF generated greater amounts of superoxide than did similar mice not expressing NIF. Importantly, NIF did not significantly impair the ability of mice to clear an opportunistic bacterial challenge, suggesting that NIF did not compromise immune surveillance. We conclude that antagonism of CD11b (integrin αmβ2 by NIF is sufficient to inhibit early stages of diabetic retinopathy, while not compromising the basic immune response.

  15. Genotoxic effects of zinc oxide nanoparticles in nasal mucosa cells are antagonized by titanium dioxide nanoparticles.

    Science.gov (United States)

    Hackenberg, Stephan; Scherzed, Agmal; Zapp, Angela; Radeloff, Katrin; Ginzkey, Christian; Gehrke, Thomas; Ickrath, Pascal; Kleinsasser, Norbert

    2017-04-01

    Titanium dioxide nanoparticles (TiO 2 -NPs) and zinc oxide nanoparticles (ZnO-NPs) are often used in sunscreens and other consumer products due to their photoprotective properties. However, concern exists regarding them possibly causing cyto- and genotoxic effects. The aim of this study was to assess cyto- and genotoxicity of these nanomaterials after single or combined exposure. For this purpose, a battery of cell culture test systems for human nasal mucosa (monolayer, air-liquid interface and mini organ culture) were exposed to 0.1-20μg/ml of TiO 2 - and ZnO-NPs alone and in combination. Cytotoxicity was measured by the MTT assay, and DNA damage and repair capacity were investigated using the comet assay. TiO 2 -NPs did not exhibit any cyto- or genotoxic potential within the tested concentrations. However, results of the study indicated cyto- and genotoxicity resulting from ZnO-NPs. The genotoxicity could be antagonized by TiO 2 -NPs. Furthermore, the DNA repair capacity after ZnO-NP-induced DNA damage was enhanced by TiO 2 -NPs. The adsorption of dissolved zinc ions onto TiO 2 -NPs is discussed as the major antagonistic mechanism. The combination of both metal oxide nanoparticles interferes with the genotoxicity of ZnO-NPs and should be discussed as a reasonable and safe alternative to the sole use of ZnO-NPs in consumer products. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Selective augmentation of striatal functional connectivity following NMDA receptor antagonism: implications for psychosis.

    Science.gov (United States)

    Dandash, Orwa; Harrison, Ben J; Adapa, Ram; Gaillard, Raphael; Giorlando, Francesco; Wood, Stephen J; Fletcher, Paul C; Fornito, Alex

    2015-02-01

    The psychotomimetic effect of the N-methyl-D-aspartate receptor (NMDAR) antagonist ketamine is thought to arise from a functional modulation of the brain's fronto-striato-thalamic (FST) circuits. Animal models suggest a pronounced effect on ventral 'limbic' FST systems, although recent work in patients with psychosis and high-risk individuals suggests specific alterations of dorsal 'associative' FST circuits. Here, we used functional magnetic resonance imaging to investigate the effects of a subanesthetic dose of ketamine on measures of functional connectivity as indexed by the temporal coherence of spontaneous neural activity in both dorsal and ventral FST circuits, as well as their symptom correlates. We adopted a placebo-controlled, double-blind, randomized, repeated-measures design in which 19 healthy participants received either an intravenous saline infusion or a racemic mixture of ketamine (100 ng/ml) separated by at least 1 week. Compared with placebo, ketamine increased functional connectivity between the dorsal caudate and both the thalamus and midbrain bilaterally. Ketamine additionally increased functional connectivity of the ventral striatum/nucleus accumbens and ventromedial prefrontal cortex. Both connectivity increases significantly correlated with the psychosis-like and dissociative symptoms under ketamine. Importantly, dorsal caudate connectivity with the ventrolateral thalamus and subthalamic nucleus showed inverse correlation with ketamine-induced symptomatology, pointing to a possible resilience role to disturbances in FST circuits. Although consistent with the role of FST in mediating psychosis, these findings contrast with previous research in clinical samples by suggesting that acute NMDAR antagonism may lead to psychosis-like experiences via a mechanism that is distinct from that implicated in frank psychotic illness.

  17. Glutamate antagonism fails to reverse mitochondrial dysfunction in late phase of experimental neonatal asphyxia in rats.

    Science.gov (United States)

    Reddy, Nagannathahalli Ranga; Krishnamurthy, Sairam; Chourasia, Tapan Kumar; Kumar, Ashok; Joy, Keerikkattil Paily

    2011-04-01

    Neonatal asphyxia is a primary contributor to neonatal mortality and neuro-developmental disorders. It progresses in two distinct phases, as initial primary process and latter as the secondary process. A dynamic relationship exists between excitotoxicity and mitochondrial dysfunction during the progression of asphyxic injury. Study of status of glutamate and mitochondrial function in tandem during primary and secondary processes may give new leads to the treatment of asphyxia. Neonatal asphyxia was induced in rat pups on the day of birth by subjecting them to two episodes (10min each) of anoxia, 24h apart by passing 100% N(2) into an enclosed chamber. The NMDA antagonist ketamine (20mg/kg/day) was administered either for 1 day or 7 days after anoxic exposure. Tissue glutamate and nitric oxide were estimated in the cerebral cortex, extra-cortex and cerebellum. The mitochondria from the above brain regions were used for the estimation of malondialdehyde, and activities of superoxide dismutase and succinate dehydrogenase. Mitochondrial membrane potential was evaluated by using Rhodamine dye. Anoxia during the primary process increased glutamate and nitric oxide levels; however the mitochondrial function was unaltered in terms of succinate dehydrogenase and membrane potential. Acute ketamine treatment reversed the increase in both glutamate and nitric oxide levels and partially attenuated mitochondrial function in terms of succinate dehydrogenase activity. The elevated glutamate and nitric oxide levels were maintained during the secondary process but however with concomitant loss of mitochondrial function. Repeated ketamine administration reversed glutamate levels only in the cerebral cortex, where as nitric oxide was decreased in all the brain regions. However, repeated ketamine administration was unable to reverse anoxia-induced mitochondrial dysfunction. The failure of glutamate antagonism in the treatment of asphyxia may be due to persistence of mitochondrial

  18. Copper Induces Vasorelaxation and Antagonizes Noradrenaline -Induced Vasoconstriction in Rat Mesenteric Artery

    Directory of Open Access Journals (Sweden)

    Yu-Chun Wang

    2013-11-01

    Full Text Available Background/Aims: Copper is an essential trace element for normal cellular function and contributes to critical physiological or pathological processes. The aim of the study was to investigate the effects of copper on vascular tone of rat mesenteric artery and compare the effects of copper on noradrenaline (NA and high K+ induced vasoconstriction. Methods: The rat mesenteric arteries were isolated and the vessel tone was measured by using multi wire myograph system in vitro. Blood pressure of carotid artery in rabbits was measured by using physiological data acquisition and analysis system in vivo. Results: Copper dose-dependently blunted NA-induced vasoconstriction of rat mesenteric artery. Copper-induced vasorelaxation was inhibited when the vessels were pretreated with NG-nitro-L-arginine methyl ester (L-NAME. Copper did not blunt high K+-induced vasoconstriction. Copper preincubation inhibited NA-evoked vasoconstriction and the inhibition was not affected by the presence of L-NAME. Copper preincubation showed no effect on high K+-evoked vasoconstriction. Copper chelator diethyldithiocarbamate trihydrate (DTC antagonized the vasoactivity induced by copper in rat mesenteric artery. In vivo experiments showed that copper injection (iv significantly decreased blood pressure of rabbits and NA or DTC injection (iv did not rescue the copper-induced hypotension and animal death. Conclusion: Copper blunted NA but not high K+-induced vasoconstriction of rat mesenteric artery. The acute effect of copper on NA-induced vasoconstriction was depended on nitric oxide (NO, but the effect of copper pretreatment on NA-induced vasoconstriction was independed on NO, suggesting that copper affected NA-induced vasoconstriction by two distinct mechanisms.

  19. Differential effects of prednisone and growth hormone on fuel metabolism and insulin antagonism in humans.

    Science.gov (United States)

    Horber, F F; Marsh, H M; Haymond, M W

    1991-01-01

    Human growth hormone (hGH) and prednisone cause insulin resistance and glucose intolerance. However, it is unknown whether hGH and prednisone antagonize insulin action on protein, fat, and carbohydrate metabolism by a common or independent mechanism. Therefore, protein, fat, and carbohydrate metabolism was assessed simultaneously in four groups of eight subjects each after 7 days of placebo, recombinant DNA hGH (rhGH; 0.1 mg.kg-1.day-1), prednisone (0.8 mg.kg-1.day-1), or rhGH and prednisone administration after an 18-h fast and during gut infusion of glucose and amino acids (fed state). Fasting plasma glucose concentrations were similar during placebo and rhGH but elevated (P less than 0.001) during combined treatment, whereas plasma insulin concentrations were higher (237 +/- 57 pmol/ml, P less than 0.001) during combined than during placebo, rhGH, or prednisone treatment (34, 52, and 91 pM, respectively). In the fed state, plasma glucose concentrations were elevated only during combined treatment (11.3 +/- 2.1 mM, P less than 0.001). Plasma insulin concentrations were elevated during therapy with prednisone alone and rhGH alone (667 +/- 72 and 564 +/- 65 pmol/ml, respectively, P less than 0.001) compared with placebo (226 +/- 44 pmol/ml) but lower than with the combined rhGH and prednisone treatment (1249 +/- 54 pmol/ml, P less than 0.01). Protein oxidation [( 14C]leucine) increased (P less than 0.001) with prednisone therapy, decreased (P less than 0.001) with rhGH treatment, and was normal during the combined treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. Differential effects of prednisone and growth hormone on fuel metabolism and insulin antagonism in humans

    Energy Technology Data Exchange (ETDEWEB)

    Horber, F.F.; Marsh, H.M.; Haymond, M.W. (Mayo Clinic, Rochester, MN (USA))

    1991-01-01

    Human growth hormone (hGH) and prednisone cause insulin resistance and glucose intolerance. However, it is unknown whether hGH and prednisone antagonize insulin action on protein, fat, and carbohydrate metabolism by a common or independent mechanism. Therefore, protein, fat, and carbohydrate metabolism was assessed simultaneously in four groups of eight subjects each after 7 days of placebo, recombinant DNA hGH (rhGH; 0.1 mg.kg-1.day-1), prednisone (0.8 mg.kg-1.day-1), or rhGH and prednisone administration after an 18-h fast and during gut infusion of glucose and amino acids (fed state). Fasting plasma glucose concentrations were similar during placebo and rhGH but elevated (P less than 0.001) during combined treatment, whereas plasma insulin concentrations were higher (237 +/- 57 pmol/ml, P less than 0.001) during combined than during placebo, rhGH, or prednisone treatment (34, 52, and 91 pM, respectively). In the fed state, plasma glucose concentrations were elevated only during combined treatment (11.3 +/- 2.1 mM, P less than 0.001). Plasma insulin concentrations were elevated during therapy with prednisone alone and rhGH alone (667 +/- 72 and 564 +/- 65 pmol/ml, respectively, P less than 0.001) compared with placebo (226 +/- 44 pmol/ml) but lower than with the combined rhGH and prednisone treatment (1249 +/- 54 pmol/ml, P less than 0.01). Protein oxidation {sup 14}C leucine increased (P less than 0.001) with prednisone therapy, decreased (P less than 0.001) with rhGH treatment, and was normal during the combined treatment.

  1. Exploring the structural basis for selenium/mercury antagonism in Allium fistulosum

    Energy Technology Data Exchange (ETDEWEB)

    McNear, Jr., David H.; Afton, Scott E.; Caruso, Joseph A. (UCIN); (Kentucky)

    2012-12-10

    While continuing efforts are devoted to studying the mutually protective effect of mercury and selenium in mammals, few studies have investigated the mercury-selenium antagonism in plants. In this study, we report the metabolic fate of mercury and selenium in Allium fistulosum (green onion) after supplementation with sodium selenite and mercuric chloride. Analysis of homogenized root extracts via capillary reversed phase chromatography coupled with inductively coupled plasma mass spectrometry (capRPLC-ICP-MS) suggests the formation of a mercury-selenium containing compound. Micro-focused synchrotron X-ray fluorescence mapping of freshly excised roots show Hg sequestered on the root surface and outlining individual root cells, while Se is more evenly distributed throughout the root. There are also discrete Hg-only, Se-only regions and an overall strong correlation between Hg and Se throughout the root. Analysis of the X-ray absorption near edge structure (XANES) spectra show a 'background' of methylselenocysteine within the root with discrete spots of SeO{sub 3}{sup 2-}, Se{sup 0} and solid HgSe on the root surface. Mercury outlining individual root cells is possibly binding to sulfhydryl groups or plasma membrane or cell wall proteins, and in some places reacting with reduced selenium in the rhizosphere to form a mercury(II) selenide species. Together with the formation of the root-bound mercury(II) selenide species, we also report on the formation of cinnabar (HgS) and Hg{sup 0} in the rhizosphere. The results presented herein shed light on the intricate chemical and biological processes occurring within the rhizosphere that influence Hg and Se bioavailability and will be instrumental in predicting the fate and assisting in the remediation of these metals in the environment and informing whether or not fruit and vegetable food selection from aerial plant compartments or roots from plants grown in Hg contaminated soils, are safe for consumption.

  2. ANTAGONISM AGAINST VIBRIO CHOLERAE BY BACTERIAL DIFFUSIBLE COMPOUND IN THE FECAL MICROBIOTA OF RODENTS

    Directory of Open Access Journals (Sweden)

    Silva Simone Helena da

    1998-01-01

    Full Text Available In an ex vivo agar plate assay, we monitored the appearance of an inhibitory halo against Vibrio cholerae from the feces of Wistar and Fischer rats aged 10 to 42 days. The frequency of Wistar rats showing halo increased from 0% (10 days to a maximum of 80.0% (29 days and then decreased to 53.3% (42 days. A similar pattern was obtained with Fischer rats but with a lower intensity (maximum frequency of 50.0% by day 36. In a separate experiment, when Wistar rats were fed a low-protein diet for 7 days, the inhibitory halo decreased drastically. Three apparently different colony morphologies were isolated from the dominant fecal microbiota: a facultative anaerobe (FAN and two strict anaerobes (SAN. The ex vivo inhibitory test showed a halo around the feces of germfree mice monoassociated with the FAN bacterium or one of the SAN bacterium but not of the germfree ones. After oral challenge of all groups with V. cholerae, a permissive and a drastic barrier effects were observed in mice with FAN and SAN associated bacteria, respectively. The FAN and one SAN bacteria used in the in vivo challenges were identified as Escherichia coli and Streptococcus intermedius, respectively. The potent antagonism developed by the rat intestinal microbiota against V. cholerae seems to be due, in part, to diffusible compounds and this phenomenon depends apparently on age, strain and nutrition of the animals. These preliminary results also suggest that this effect was due to more than one bacterial component at any given moment.

  3. Something Blossoms in Between: Silence-Phenomena as a Bordering Notions in Psychology.

    Science.gov (United States)

    Lehmann Oliveros, Olga V

    2016-03-01

    Mysterious yet unavoidable, silence-phenomena appear to us in inherent ambiguity. In its plurality of meanings, phenomena related to silence are often perceived as overwhelming because they transcend the communicative capacity of language making it a challenge for cultural psychology to understand its involvement in our processes of making sense of experience and existence. Human growth and development involve processes where presence, void and content, voice, sound and noise, motion, transition and stillness, have dialectic interactions. In this article I discuss silence-phenomena as a bordering notion in terms of its discursive quality, the silent quality of speech, and the awareness of the ineffable. In addition, I highlight the possible implications of such notion in the understanding of affect from the perspective of Semiotic Cultural Psychology. I also emphasize the importance of considering psychological borders as multi-dimensional, taking the phenomenological experience of temporality as an illustration, which is also related to high emotional involvement of attention.

  4. How abusive supervisors influence employees' voice and silence: the effects of interactional justice and organizational attribution.

    Science.gov (United States)

    Wang, Rong; Jiang, Jiang

    2015-01-01

    In this research we investigated the influence of abusive supervision on employees' prosocial voice and silence, as well as clarified the roles of interactional justice (as a mediator) and organizational attribution (as a moderator). Moreover, we examined a mediated moderating model stipulating that interactional justice mediated the moderating effect of organizational attribution on the focal relationship. A scenario experiment was employed in Study 1, and after analyzing data from 196 employees, we found that abusive supervision influenced employees' prosocial voice and silence via interactional justice. In Study 2, data were collected from 379 employees in two waves separated by 1 week. The results not only replicated the findings of Study 1 but also indicated that organizational attribution buffered the abusive supervision-voice and silence relationship, and that interactional justice mediated this moderating effect.

  5. Virus-Induced Gene Silencing in Maize with a Foxtail mosaic virus Vector.

    Science.gov (United States)

    Mei, Yu; Whitham, Steven A

    2018-01-01

    Virus-induced gene silencing (VIGS) is a powerful technology for rapidly and transiently knocking down the expression of plant genes to study their functions. A VIGS vector for maize derived from Foxtail mosaic virus (FoMV), a positive-sense single-stranded RNA virus, was recently developed. A cloning site created near the 3' end of the FoMV genome enables insertion of 200-400 nucleotide fragments of maize genes targeted for silencing. The recombinant FoMV clones are inoculated into leaves of maize seedlings by biolistic particle delivery, and silencing is typically observed within 2 weeks after inoculation. This chapter provides a protocol for constructing FoMV VIGS clones and inoculating them into maize seedlings.

  6. RNA interference silencing of CHS greatly alters the growth pattern of apple (Malus x domestica).

    Science.gov (United States)

    Dare, Andrew P; Hellens, Roger P

    2013-08-01

    Plants produce a vast array of phenolic compounds which are essential for their survival on land. One major class of polyphenols are the flavonoids and their formation is dependent on the enzyme chalcone synthase (CHS). In a recent study we silenced the CHS genes of apple (Malus × domestica Borkh.) and observed a loss of pigmentation in the fruit skin, flowers and stems. More surprisingly, highly silenced lines were significantly reduced in size, with small leaves and shortened internode lengths. Chemical analysis also revealed that the transgenic shoots contained greatly reduced concentrations of flavonoids which are known to modulate auxin flow. An auxin transport study verified this, with an increased auxin transport in the CHS-silenced lines. Overall, these findings suggest that auxin transport in apple has adapted to take place in the presence of high endogenous concentrations of flavonoids. Removal of these compounds therefore results in abnormal auxin movement and a highly disrupted growth pattern.

  7. V2 from a curtovirus is a suppressor of post-transcriptional gene silencing.

    Science.gov (United States)

    Luna, Ana P; Rodríguez-Negrete, Edgar A; Morilla, Gabriel; Wang, Liping; Lozano-Durán, Rosa; Castillo, Araceli G; Bejarano, Eduardo R

    2017-10-01

    The suppression of gene silencing is a key mechanism for the success of viral infection in plants. DNA viruses from the Geminiviridae family encode several proteins that suppress transcriptional and post-transcriptional gene silencing (TGS/PTGS). In Begomovirus, the most abundant genus of this family, three out of six genome-encoded proteins, namely C2, C4 and V2, have been shown to suppress PTGS, with V2 being the strongest PTGS suppressor in transient assays. Beet curly top virus (BCTV), the model species for the Curtovirus genus, is able to infect the widest range of plants among geminiviruses. In this genus, only one protein, C2/L2, has been described as inhibiting PTGS. We show here that, despite the lack of sequence homology with its begomoviral counterpart, BCTV V2 acts as a potent PTGS suppressor, possibly by impairing the RDR6 (RNA-dependent RNA polymerase 6)/suppressor of gene silencing 3 (SGS3) pathway.

  8. Gold Nanorod-siRNA Induces Efficient In Vivo Gene Silencing in the Rat Hippocampus

    Science.gov (United States)

    Bonoiu, Adela C.; Bergey, Earl J.; Ding, Hong; Hu, Rui; Kumar, Rajiv; Yong, Ken-Tye; Prasad, Paras N.; Mahajan, Supriya; Picchione, Kelly E.; Bhattacharjee, Arin; Ignatowski, Tracey A.

    2011-01-01

    Gold nanorods (GNRs), cellular imaging nanoprobes, have been used for drug delivery therapy to immunologically privileged regions in the brain. We demonstrate that nanoplexes formed by electrostatic binding between negatively charged RNA and positively charged GNRs, silence the expression of the target housekeeping gene, glyceraldehyde 3-phosphate dehydrogenase (GAPDH) within the CA1 hippocampal region of the rat brain, without showing cytotoxicity. Fluorescence imaging with siRNACy3GAPDH and dark field imaging using plasmonic enhanced scattering from GNRs were used to monitor the distribution of the nanoplexes within different neuronal cell types present in the targeted hippocampal region. Our results show robust nanoplex uptake and slow release of the fluorescent gene silencer with significant impact on suppression of GAPDH gene expression (70% gene silencing, >10 days post-injection). The observed gene knockdown using nanoplexes in targeted regions of the brain opens a new era of drug treatment for neurological disorders. PMID:21718174

  9. Mechanisms of epigenetic silencing of the c21 gene in Y1 adrenocortical tumor cells.

    Science.gov (United States)

    Szyf, M; Slack, A D

    2000-11-01

    We utilized Y1 adrenocortical carcinoma cell line as a model system to dissect the events regulating epigenomic gene silencing in tumor cells. We show here that the chromatin structure of c21 gene is inactive in Y1 cells and that it could be reconfigured to an active form by either expressing antisense mRNA to DNA methyltransferase 1 (dnmt1) or an attenuator of Ras protooncogenic signaling hGAP. Surprisingly however, the known inducer of active chromatin structure the histone deacetylase inhibitor trichostatin A TSA fails to induce expression of c21. These results suggest that the primary cause of c21 gene silencing is independent of histone deacetylation. We present a model to explain the possible roles of the different components of the epigenome and the DNA methylation and demethylation machineries in silencing c21 gene expression.

  10. Smuggling gold nanoparticles across cell types - A new role for exosomes in gene silencing.

    Science.gov (United States)

    Roma-Rodrigues, Catarina; Pereira, Francisca; Alves de Matos, António P; Fernandes, Marta; Baptista, Pedro V; Fernandes, Alexandra R

    2017-05-01

    Once released to the extracellular space, exosomes enable the transfer of proteins, lipids and RNA between different cells, being able to modulate the recipient cells' phenotypes. Members of the Rab small GTP-binding protein family, such as RAB27A, are responsible for the coordination of several steps in vesicle trafficking, including budding, mobility, docking and fusion. The use of gold nanoparticles (AuNPs) for gene silencing is considered a cutting-edge technology. Here, AuNPs were functionalized with thiolated oligonucleotides anti-RAB27A (AuNP@PEG@anti-RAB27A) for selective silencing of the gene with a consequent decrease of exosomes´ release by MCF-7 and MDA-MB-453 cells. Furthermore, communication between tumor and normal cells was observed both in terms of alterations in c-Myc gene expression and transportation of the AuNPs, mediating gene silencing in secondary cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Long Double-Stranded Multiplex siRNAs for Dual Genes Silencing

    Science.gov (United States)

    Peng, Wei; Chen, Jianxin; Qin, Yinchao; Yang, Zhenjun

    2013-01-01

    Simultaneous suppression of multiple oncogenes is an attractive strategy to treat cancers. Herein we present a series of long double-stranded multiplex small interfering RNAs (multi-siRNAs) that is suitable for dual genes silencing through a sequence-specific RNA interference process without inducing significant immune responses. A gap feature structurally designed in either of the nucleotide strands of the multi-siRNAs was proved to be essential toward silencing target genes and avoiding immune responses. Furthermore, the silencing effect of multi-siRNAs against SURVIVIN and BCL-2 genes was shown to be effective and resulted in up-regulation of caspase-3 related apoptosis and, in turn, inhibition of bladder cancer cell proliferation. Our observation suggested that the rationally designed multi-siRNAs would have great potential for therapeutic siRNA design. PMID:23656495

  12. Use of guanidinopropyl-modified siRNAs to silence gene expression.

    Science.gov (United States)

    Buff, Maximilian C R; Bernhardt, Stefan; Marimani, Musa D; Ely, Abdullah; Engels, Joachim W; Arbuthnot, Patrick

    2015-01-01

    Silencing gene expression by harnessing the RNA interference (RNAi) pathway with short interfering RNAs (siRNAs) has useful analytical and potentially therapeutic application. To augment silencing efficacy of siRNAs, chemical modification has been employed to improve stability, target specificity, and delivery to target tissues. siRNAs incorporating guanidinopropyl (GP) moieties have demonstrated enhanced target gene silencing in cell culture and in vivo models of hepatitis B virus replication. Here we describe the synthesis of GP-modified siRNAs and use of 5' rapid amplification of cDNA ends (5' RACE) to verify an RNAi-mediated mechanism of action of these novel chemically modified siRNAs.

  13. Transgene-induced gene silencing is not affected by a change in ploidy level.

    Directory of Open Access Journals (Sweden)

    Daniela Pignatta

    Full Text Available BACKGROUND: Whole genome duplication, which results in polyploidy, is a common feature of plant populations and a recurring event in the evolution of flowering plants. Polyploidy can result in changes to gene expression and epigenetic instability. Several epigenetic phenomena, occurring at the transcriptional or post-transcriptional level, have been documented in allopolyploids (polyploids derived from species hybrids of Arabidopsis thaliana, yet findings in autopolyploids (polyploids derived from the duplication of the genome of a single species are limited. Here, we tested the hypothesis that an increase in ploidy enhances transgene-induced post-transcriptional gene silencing using autopolyploids of A. thaliana. METHODOLOGY/PRINCIPAL FINDINGS: Diploid and tetraploid individuals of four independent homozygous transgenic lines of A. thaliana transformed with chalcone synthase (CHS inverted repeat (hairpin constructs were generated. For each line diploids and tetraploids were compared for efficiency in post-transcriptional silencing of the endogenous CHS gene. The four lines differed substantially in their silencing efficiency. Yet, diploid and tetraploid plants derived from these plants and containing therefore identical transgene insertions showed no difference in the efficiency silencing CHS as assayed by visual scoring, anthocyanin assays and quantification of CHS mRNA. CONCLUSIONS/SIGNIFICANCE: Our results in A. thaliana indicated that there is no effect of ploidy level on transgene-induced post-transcriptional gene silencing. Our findings that post-transcriptional mechanisms were equally effective in diploids and tetraploids supports the use of transgene-driven post-transcriptional gene silencing as a useful mechanism to modify gene expression in polyploid species.

  14. Gene silencing for epidermal growth factor receptor variant III induces cell-specific cytotoxicity.

    Science.gov (United States)

    Yamoutpour, Farnaz; Bodempudi, Vidya; Park, Shay E; Pan, Weihong; Mauzy, Mary Jean; Kratzke, Robert A; Dudek, Arkadiusz; Potter, David A; Woo, Richard A; O'Rourke, Donald M; Tindall, Donald J; Farassati, Faris

    2008-11-01

    Epidermal growth factor receptor variant III (EGFRvIII) is a constitutively active mutant form of EGFR that is expressed in 40% to 50% of gliomas and several other malignancies. Here, we describe the therapeutic effects of silencing EGFRvIII on glioma cell lines in vitro and in vivo. A small interfering RNA molecule against EGFRvIII was introduced into EGFRvIII-expressing glioma cells (U87Delta) by electroporation resulting in complete inhibition of expression of EGFRvIII as early as 48 h post-treatment. During EGFRvIII silencing, a decrease in the proliferation and invasiveness of U87Delta cells was accompanied by an increase in apoptosis (P < 0.05). Notably, EGFRvIII silencing inhibited the signal transduction machinery downstream of EGFRvIII as evidenced by decreases in the activated levels of Ras and extracellular signal-regulated kinase. A lentivirus capable of expressing anti-EGFRvIII short hairpin RNA was also able to achieve progressive silencing of EGFRvIII in U87Delta cells in addition to inhibiting cell proliferation, invasiveness, and colony formation in a significant manner (P < 0.05). Silencing EGFRvIII in U87Delta cultures with this virus reduced the expression of factors involved in epithelial-mesenchymal transition including N-cadherin, beta-catenin, Snail, Slug, and paxillin but not E-cadherin. The anti-EGFRvIII lentivirus also affected the cell cycle progression of U87Delta cells with a decrease in G(1) and increase in S and G(2) fractions. In an in vivo model, tumor growth was completely inhibited in severe combined immunodeficient mice (n = 10) injected s.c. with U87Delta cells treated with the anti-EGFRvIII lentivirus (P = 0.005). We conclude that gene specific silencing of EGFRvIII is a promising strategy for treating cancers that contain this mutated receptor.

  15. The Impact of Gene Silencing on Horizontal Gene Transfer and Bacterial Evolution.

    Science.gov (United States)

    Navarre, W W

    2016-01-01

    The H-NS family of DNA-binding proteins is the subject of intense study due to its important roles in the regulation of horizontally acquired genes critical for virulence, antibiotic resistance, and metabolism. Xenogeneic silencing proteins, typified by the H-NS protein of Escherichia coli, specifically target and downregulate expression from AT-rich genes by selectively recognizing specific structural features unique to the AT-rich minor groove. In doing so, these proteins facilitate bacterial evolution; enabling these cells to engage in horizontal gene transfer while buffering potential any detrimental fitness consequences that may result from it. Xenogeneic silencing and counter-silencing explain how bacterial cells can evolve effective gene regulatory strategies in the face of rampant gene gain and loss and it has extended our understanding of bacterial gene regulation beyond the classic operon model. Here we review the structures and mechanisms of xenogeneic silencers as well as their impact on bacterial evolution. Several H-NS-like proteins appear to play a role in facilitating gene transfer by other mechanisms including by regulating transposition, conjugation, and participating in the activation of virulence loci like the locus of enterocyte effacement pathogenicity island of pathogenic strains of E. coli. Evidence suggests that the critical determinants that dictate whether an H-NS-like protein will be a silencer or will perform a different function do not lie in the DNA-binding domain but, rather, in the domains that control oligomerization. This suggests that H-NS-like proteins are transcription factors that both recognize and alter the shape of DNA to exert specific effects that include but are not limited to gene silencing. © 2016 Elsevier Ltd All rights reserved.

  16. The effects of sedative music, arousal music, and silence on electrocardiography signals.

    Science.gov (United States)

    Dousty, Mehdy; Daneshvar, Sabalan; Haghjoo, Majid

    2011-01-01

    Research indicates that music can affect heart rate, blood pressure, and skin conductance. Music can stimulate central emotions in the brain and release biochemical materials that change the physiologic state. We sought to compare changes in the electrical function of the heart in response to music. Subjects were asked to listen to 2 types of music, namely, sedative and arousal music, in conjunction with two 30-second periods of complete silence. The experiment was conducted in 4 segments: the first and third parts were silence, and the second and fourth parts were music. First, the response to each type of music was compared with that to the preceding period of silence. Next, the responses to both types of music were compared. Finally, the response to music regardless of the type was compared with that to silence. The amplitude of polarization and depolarization changed in response to different kinds of music. The electrical function of the heart in response to music, irrespective of the music type, differed from that in response to silence. The 2 types of music impacted the electrical function of the heart in different ways: the arousal music influenced T-wave maximum amplitude, whereas no such change was recorded in response to the sedative music. The bandwidth of the polarization and depolarization of the heart rate and R-wave amplitude increased in response to music by comparison with silence. In addition, the heart did not seem to try to synchronize with music. The mean R-wave amplitude in sedative music is higher than the arousal music, so our heart works differently when different types of music are heard. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Organizational Silence Among Nurses: The Impact on Organizational Cynicism and Intention to Leave Work.

    Science.gov (United States)

    Çaylak, Esra; Altuntaş, Serap

    2017-04-01

    In recent years, organizational silence and organizational cynicism, factors that have been shown to inhibit the improvement of organizations, have been highlighted in the health sector. Nearly every aspect of these two issues has been studied. This research was conducted to identify the relationship between the organizational silence, organizational cynicism, and intention to leave work of nurses. This descriptive and correlational study was carried out in August and September 2013 with 323 nurses at a university hospital in Ankara. A questionnaire that includes a personal information form, the Organizational Silence Scale, the Organizational Cynicism Scale, and a question about intention to leave work was used. Ethics committee approval and institutional permissions were obtained. A statistician analyzed the data. The present research found administrative and organizational reasons to be the most important reason why participants remain silent (M = 35.4 ± 13.1), with the tendency not to speak up about ethics and responsibility issues the second most important reason (M = 17.3 ± 6.5). The organizational cynicism of participants is at an intermediate level (M = 36.4 ± 9.6) and may be characterized as cognitive (M = 14.6 ± 4.3). Approximately half of the participants had never considered leaving work. For the participants in this study, organizational silence particularly influences organizational cynicism. The reasons for organizational silence in conjunction with organizational cynicism increase intent to leave work (R = .395, R = .156, p < .001). This study found that the reasons for organizational silence and organizational cynicism influence the intention of nurses to leave work. The reasons that lead nurses to become silent, to experience cynicism, and to leave work in healthcare environments should be identified. Programs and activities to replace negative ideas with positive ideas should be implemented.

  18. Endothelin A receptor antagonism in experimental congestive heart failure results in augmentation of the renin-angiotensin system and sustained sodium retention.

    Science.gov (United States)

    Schirger, John A; Chen, Horng H; Jougasaki, Michihisa; Lisy, Ondrej; Boerrigter, Guido; Cataliotti, Alessandro; Burnett, John C

    2004-01-20

    While both the endothelin-1 (ET-1) and renin-angiotensin systems (RAS) are activated in congestive heart failure (CHF), the temporal sequence of this activation remains unclear. Understanding this pattern of neurohumoral activation may aid in understanding the significance of ET-1 in CHF and provide strategies for ET-1 antagonism. Although acute endothelin (ET) receptor antagonism improves systemic hemodynamics in CHF, clinical trials with chronic ET receptor antagonism report worsening CHF symptoms. In a canine model of progressive left ventricular dysfunction, we demonstrated activation of myocardial and plasma ET-1 without activation of the RAS during transition to overt CHF, suggesting that ET-1 contributes to this transition. We next evaluated the effects of chronic oral ET-A receptor antagonism on neurohumoral function, renal hemodynamics, and sodium excretion in pacing-induced CHF. After 7 days of treatment (n=7) with ET-A receptor antagonism (with LU135252), sodium excretion did not improve in treated versus untreated CHF (n=6). Furthermore, both plasma renin activity and plasma ET-1 increased with ET-A receptor blockade. Activation of the myocardial and plasma ET-1 systems precedes activation of the myocardial and plasma RAS in CHF. ET-A receptor antagonism in experimental CHF further activates the RAS without improving sodium excretion. These findings suggest an important role for ET-1 in the progression of CHF and a potential mechanism for the exacerbation of CHF symptoms observed in clinical trials with chronic ET receptor antagonism. Further studies with combined modulation of the ET and other neurohumoral systems in CHF are required.

  19. H-NS silences gfp, the green fluorescent protein gene: gfpTCD is a genetically Remastered gfp gene with reduced susceptibility to H-NS-mediated transcription silencing and with enhanced translation.

    Science.gov (United States)

    Corcoran, Colin P; Cameron, Andrew D S; Dorman, Charles J

    2010-09-01

    The bacterial nucleoid-associated protein H-NS, which preferentially targets and silences A+T-rich genes, binds the ubiquitous reporter gene gfp and dramatically reduces local transcription. We have redesigned gfp to reduce H-NS-mediated transcription silencing and simultaneously improve translation in vivo without altering the amino acid sequence of the GFP protein.

  20. Optimized cDNA libraries for virus-induced gene silencing (VIGS using tobacco rattle virus

    Directory of Open Access Journals (Sweden)

    Page Jonathan E

    2008-01-01

    Full Text Available Abstract Background Virus-induced gene silencing (VIGS has emerged as a method for performing rapid loss-of-function experiments in plants. Despite its expanding use, the effect of host gene insert length and other properties on silencing efficiency have not been systematically tested. In this study, we probed the optimal properties of cDNA fragments of the phytoene desaturase (PDS gene for efficient VIGS in Nicotiana benthamiana using tobacco rattle virus (TRV. Results NbPDS inserts of between 192 bp and 1304 bp led to efficient silencing as determined by analysis of leaf chlorophyll a levels. The region of the NbPDS cDNA used for silencing had a small effect on silencing efficiency with 5' and 3' located inserts performing more poorly than those from the middle. Silencing efficiency was reduced by the inclusion of a 24 bp poly(A or poly(G homopolymeric region. We developed a method for constructing cDNA libraries for use as a source of VIGS-ready constructs. Library construction involved the synthesis of cDNA on a solid phase support, digestion with RsaI to yield short cDNA fragments lacking poly(A tails and suppression subtractive hybridization to enrich for differentially expressed transcripts. We constructed two cDNA libraries from methyl-jasmonate treated N. benthamiana roots and obtained 2948 ESTs. Thirty percent of the cDNA inserts were 401–500 bp in length and 99.5% lacked poly(A tails. To test the efficiency of constructs derived from the VIGS-cDNA libraries, we silenced the nicotine biosynthetic enzyme, putrescine N-methyltransferase (PMT, with ten different VIGS-NbPMT constructs ranging from 122 bp to 517 bp. Leaf nicotine levels were reduced by more than 90% in all plants infected with the NbPMT constructs. Conclusion Based on the silencing of NbPDS and NbPMT, we suggest the following design guidelines for constructs in TRV vectors: (1 Insert lengths should be in the range of ~200 bp to ~1300 bp, (2 they should be positioned in

  1. Design of a PROTAC that antagonizes and destroys the cancer-forming X-protein of the hepatitis B virus

    Energy Technology Data Exchange (ETDEWEB)

    Montrose, Kristopher; Krissansen, Geoffrey W., E-mail: gw.krissansen@auckland.ac.nz

    2014-10-31

    Highlights: • A novel proteolysis targeting chimeric molecule (PROTAC) to treat hepatitis B. • The PROTAC antagonizes and destroys the X-protein of the hepatitis B virus. • The PROTAC is a fusion of the X-protein oligomerization and instability domains. • The oligomerization domain is a dominant-negative inhibitor of X-protein function. • X-protein-targeting PROTACs have potential to prevent hepatocellular carcinoma. - Abstract: The X-protein of the hepatitis B virus (HBV) is essential for virus infection and contributes to the development of HBV-induced hepatocellular carcinoma (HCC), a disease which causes more than one million deaths each year. Here we describe the design of a novel PROTAC (proteolysis targeting chimeric molecule) capable of simultaneously inducing the degradation of the X-protein, and antagonizing its function. The PROTAC was constructed by fusing the N-terminal oligomerization and C-terminal instability domains of the X-protein to each other, and rendering them cell-permeable by the inclusion of a polyarginine cell-penetrating peptide (CPP). It was predicted that the oligomerization domain would bind the X-protein, and that the instability domain would cause the X-protein to be targeted for proteasomal degradation. Addition of the PROTAC to HepG2 liver cancer cells, engineered to express full-length and C-terminally truncated forms of the X-protein, resulted in the degradation of both forms of the X-protein. A cell-permeable stand-alone form of the oligomerization domain was taken up by HepG2 cells, and acted as a dominant-negative inhibitor, causing inhibition of X-protein-induced apoptosis. In summary, the PROTAC described here induces the degradation of the X-protein, and antagonizes its function, and warrants investigation in a preclinical study for its ability to prevent or treat HBV infection and/or the development of HCC.

  2. Neuromuscular blocking effects of cisatracurium and its antagonism with neostigmine in a canine model of autosomal-recessive centronuclear myopathy.

    Science.gov (United States)

    Martin-Flores, M; Paré, M D; Campoy, L; Gleed, R D

    2015-12-01

    Centronuclear myopathy (CNM) is a rare congenital condition associated with skeletal muscle weakness. Patients with CNM may have decreased acetylcholine receptor expression and a reduced number of releasable quanta. Such perturbations could affect the time-course of neuromuscular blocking agents (NMBAs) and their antagonism with cholinesterase inhibitors. As a result of the rarity of CNM, prospective data regarding NMBA use in this subpopulation is scarce. We evaluated the neuromuscular blocking effects of cisatracurium and its antagonism with neostigmine in a canine model of CNM. Six dogs with congenital autosomal-recessive CNM and six controls received cisatracurium 0.15 mg kg(-1) i.v. under general anaesthesia and intermittent positive pressure ventilation. Neuromuscular function was monitored with acceleromyography.When the second response (T2) to train-of-four (TOF) stimulation returned, neostigmine 0.04 mg kg(-1) (with glycopyrrolate) were administered i.v. The onset time, time to spontaneous return of T2, and the time to reach a TOF ratio ≥0.9 after neostigmine administration were recorded. Onset time was no different between groups. Median (interquartile range) time to return of T2 was 27 (24-31) min for control dogs and 26 (22-31) min for CNM dogs (P=0.93).After neostigmine administration, a TOF ratio ≥0.9 was reached in 12 (10-15) min and 17 (16-19) min in control and CNM, respectively (P=0.005). The spontaneous return of T2 was not different between groups. However, neostigmine-facilitated recovery was significantly slower in dogs with CNM. Canine autosomal-recessive CNM does not preclude the use of cisatracurium or its antagonism with neostigmine. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. [Population dynamics and antagonism toward Fusarium oxysporium f. sp. Vasinfectum. and Verticillium dahliae Kleb of endophytic bacteria from cotton].

    Science.gov (United States)

    Li, Chunhong; Deng, Yuanyu; Zhao, Mingwen; Tang, Canming; Li, Shunpeng; Lv, Haiwei

    2009-09-01

    To explore population dynamics of endophytic bacteria and obtain antagonistic endophytic bacteria toward Verticillium dahliae Kleb (Vd), Fusarium oxysporium f. sp. Vasinfectum (Fov) from cotton. Root, stem and leaf samples were surface-disinfested, and subsequently used to isolate endophytic bacteria by diluting plate counting method. We assayed antagonism of the isolated endophytic bacteria toward three pathogens: Vd (V107, which is a highly virulent defoliating isolate and V396, which is a mildly virulent non-defoliating isolate), Fov (F108) using a dual culture method, and analyzed the 16S rDNA sequence of doubly antagonistic endophytic bacteria (DAEB) isolates toward both Vd and Fov. The population size of endophytic bacteria in root was significantly larger than that in leaf and stem. The populations at seedling stage were generally lower than those at the flowering/maturing stage in root, the populations in stem and leaf were fluctuant at different development stages, but variation law was not observed obviously. Furthermore, although no significant differences of the population densities in root were found among 6 cotton cultivars, the population densities in stem and leaf showed cultivar differences. The proportion of endophytic bacteria antagonizing Vd (V107, V396) and Fov (F108) in root was higher than that in stem/leaf, moreover, the amount of endophytic bacteria antagonizing toward V107 was less than that toward V396/F108. Based on 16S rDNA sequence analysis, all 44 DAEB isolates consisted of two phyla, i.e., Bacteroidetes (1 out of 44) and Proteobacteria (43 out of 44), and fell into 8 genera. The genus enterobacter (18 out of 44) and Pantoea (15 out of 44) were predominant. Notably, ten DAEB isolates demonstrated bacteria. We discovered that DAEB with predominant and various genus existed in cotton. Endophytic bacteria in cotton could serve as a pool for discovering biocontrol agent toward cotton pathogens.

  4. Biocontrol bacteria selected by a direct plant protection strategy against avocado white root rot show antagonism as a prevalent trait.

    Science.gov (United States)

    González-Sánchez, M Á; Pérez-Jiménez, R M; Pliego, C; Ramos, C; de Vicente, A; Cazorla, F M

    2010-07-01

    This study was undertaken to study bacterial strains obtained directly for their efficient direct control of the avocado white root rot, thus avoiding prescreening by any other possible mechanism of biocontrol which could bias the selection. A collection of 330 bacterial isolates was obtained from the roots and soil of healthy avocado trees. One hundred and forty-three representative bacterial isolates were tested in an avocado/Rosellinia test system, resulting in 22 presumptive protective strains, all of them identified mainly as Pseudomonas and Bacillus species. These 22 candidate strains were screened in a more accurate biocontrol trial, confirming protection of some strains (4 out of the 22). Analyses of the potential bacterial traits involved in the biocontrol activity suggest that different traits could act jointly in the final biocontrol response, but any of these traits were neither sufficient nor generalized for all the active bacteria. All the protective strains selected were antagonistic against some fungal root pathogens. Diverse bacteria with biocontrol activity could be obtained by a direct plant protection strategy of selection. All the biocontrol strains finally selected in this work were antagonistic, showing that antagonism is a prevalent trait in the biocontrol bacteria selected by a direct plant protection strategy. This is the first report on the isolation of biocontrol bacterial strains using direct plant protection strategy in the system avocado/Rosellinia. Characterization of selected biocontrol bacterial strains obtained by a direct plant protection strategy showed that antagonism is a prevalent trait in the selected strains in this experimental system. This suggests that antagonism could be used as useful strategy to select biocontrol strains. © 2009 The Authors. Journal compilation © 2009 The Society for Applied Microbiology.

  5. NMDA Receptor Agonism and Antagonism within the Amygdaloid Central Nucleus Suppresses Pain Affect: Differential Contribution of the Ventrolateral Periaqueductal Gray

    Science.gov (United States)

    Spuz, Catherine A.; Tomaszycki, Michelle L.; Borszcz, George S.

    2015-01-01

    The amygdala contributes to the generation of pain affect and the amygdaloid central nucleus (CeA) receives nociceptive input that is mediated by glutamatergic neurotransmission. The present study compared the contribution of N-methyl-D-aspartate (NMDA) receptor agonism and antagonism in CeA to generation of the affective response of rats to an acute noxious stimulus. Vocalizations that occur following a brief tail shock (vocalization afterdischarges) are a validated rodent model of pain affect, and were preferentially suppressed, in a dose dependent manner, by bilateral injection into CeA of NMDA (.1 µg, .25 µg, .5 µg, or 1 µg/side), or the NMDA receptor antagonist D-2-amino-5-phosphonovalerate (AP5, 1 µg, 2 µg, or 4 µg/side). Vocalizations that occur during tail shock were suppressed to a lesser degree, whereas, spinal motor reflexes (tail flick and hind limb movements) were unaffected by injection of NMDA or AP5 into CeA. Injection of NMDA, but not AP5, into CeA increased c-Fos immunoreactivity in the ventrolateral periaqueductal gray (vlPAG), and unilateral injection of the µ-opiate receptor antagonist H-D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP, 0.25 µg) into vlPAG prevented the antinociception generated by injection of NMDA into CeA. These findings demonstrate that although NMDA receptor agonism and antagonism in CeA produce similar suppression of pain behaviors they do so via different neurobiological mechanisms. Perspective The amygdala contributes to production of the emotional dimension of pain. NMDA receptor agonism and antagonism within the central nucleus of the amygdala suppressed rats’ emotional response to acute painful stimulation. Understanding the neurobiology underlying emotional responses to pain will provide insights into new treatments for pain and its associated affective disorders. PMID:25261341

  6. An Investigation of Acoustic Attenuation Performance of Silencers with Mean Flow Based on Three-Dimensional Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Wei Fan

    2016-01-01

    Full Text Available Transmission loss (TL is often used to evaluate the acoustic attenuation performance of a silencer. In this work, a three-dimensional (3D finite element method (FEM is employed to calculate the TL of some representative silencers, namely, circular expansion chamber silencer and straight-through perforated pipe silencer. In order to account for the effect of mean flow that exists inside the silencer, the 3D FEM is used in conjunction with the Computational Fluid Dynamics (CFD simulation of the flow field. More concretely, the 3D mean flow field is computed by firstly using CFD, and then the obtained mean flow data are imported to an acoustic solution undertaken using FEM. The data transfer between the two steps is accomplished by mesh mapping. The results presented demonstrate good agreement between present TL predictions and previously published experimental and numerical works. Also, the details of the flow inside the silencers may be studied. Furthermore, the effect of mean flow velocity on acoustic attenuation performance of the silencers is investigated. It is concluded that for the studied silencers, in general, increasing flow velocity increases the TL and decreases the resonance peaks.

  7. Host-induced gene silencing: a tool for understanding fungal host interaction and for developing novel disease control strategies.

    Science.gov (United States)

    Nunes, Cristiano C; Dean, Ralph A

    2012-06-01

    Recent discoveries regarding small RNAs and the mechanisms of gene silencing are providing new opportunities to explore fungal pathogen-host interactions and potential strategies for novel disease control. Plant pathogenic fungi are a constant and major threat to global food security; they represent the largest group of disease-causing agents on crop plants on the planet. An initial understanding of RNA silencing mechanisms and small RNAs was derived from model fungi. Now, new knowledge with practical implications for RNA silencing is beginning to emerge from the study of plant-fungus interactions. Recent studies have shown that the expression of silencing constructs in plants designed on fungal genes can specifically silence their targets in invading pathogenic fungi, such as Fusarium verticillioides, Blumeria graminis and Puccinia striiformis f.sp. tritici. Here, we highlight the important general aspects of RNA silencing mechanisms and emphasize recent findings from plant pathogenic fungi. Strategies to employ RNA silencing to investigate the basis of fungal pathogenesis are discussed. Finally, we address important aspects for the development of fungal-derived resistance through the expression of silencing constructs in host plants as a powerful strategy to control fungal disease. © 2011 The Authors. Molecular Plant Pathology © 2011 BSPP and Blackwell Publishing Ltd.

  8. The influenza A virus NS1 protein binds small interfering RNAs and suppresses RNA silencing in plants

    NARCIS (Netherlands)

    Bucher, E.C.; Hemmes, J.C.; Haan, de P.; Goldbach, R.W.; Prins, M.W.

    2004-01-01

    RNA silencing comprises a set of sequence-specific RNA degradation pathways that occur in a wide range of eukaryotes, including animals, fungi and plants. A hallmark of RNA silencing is the presence of small interfering RNA molecules (siRNAs). The siRNAs are generated by cleavage of larger

  9. Uudised : Rannap sai raha lõpuks kätte. No Big Silence esitleb uut heliplaati

    Index Scriptorium Estoniae

    2000-01-01

    Pärnus toimunud lühima öö laulukonkursil võitis peaauhinna R. Rannap. Ans. No-Big-Silence on soojendusbändiks 2. juulil Tallinna Lauluväljakul toimuval Iron Maideni kontserdil. Ans. No-Big-Silence esitleb oma uut heliplaati "successful, bitch and beautiful"

  10. Novel anti-HER2 monoclonal antibodies: synergy and antagonism with tumor necrosis factor-α

    Directory of Open Access Journals (Sweden)

    Ceran Ceyhan

    2012-10-01

    , but antagonistically on BT-474 cells. A representative anti-HER2 antibody inhibited Akt and ERK1/2 phosphorylation leading to cyclin D1 accumulation and growth arrest in SK-BR-3 cells, independently from TNF-α. Conclusions Novel antibodies against extracellular domain of HER2 may serve as potent anti-cancer bioactive molecules. Cell-dependent synergy and antagonism between anti-HER2 antibodies and TNF-α provide evidence for a complex interplay between HER2 and TNF-α signaling pathways. Such complexity may drastically affect the outcome of HER2-directed therapeutic interventions.

  11. Feline Immunodeficiency Virus Evolutionarily Acquires Two Proteins, Vif and Protease, Capable of Antagonizing Feline APOBEC3.

    Science.gov (United States)

    Yoshikawa, Rokusuke; Takeuchi, Junko S; Yamada, Eri; Nakano, Yusuke; Misawa, Naoko; Kimura, Yuichi; Ren, Fengrong; Miyazawa, Takayuki; Koyanagi, Yoshio; Sato, Kei

    2017-06-01

    The interplay between viral and host proteins has been well studied to elucidate virus-host interactions and their relevance to virulence. Mammalian genes encode apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (APOBEC3) proteins, which act as intrinsic restriction factors against lentiviruses. To overcome APOBEC3-mediated antiviral actions, lentiviruses have evolutionarily acquired an accessory protein, viral infectivity factor (Vif), and Vif degrades host APOBEC3 proteins via a ubiquitin/proteasome-dependent pathway. Although the Vif-APOBEC3 interaction and its evolutionary significance, particularly those of primate lentiviruses (including HIV) and primates (including humans), have been well investigated, those of nonprimate lentiviruses and nonprimates are poorly understood. Moreover, the factors that determine lentiviral pathogenicity remain unclear. Here, we focus on feline immunodeficiency virus (FIV), a pathogenic lentivirus in domestic cats, and the interaction between FIV Vif and feline APOBEC3 in terms of viral virulence and evolution. We reveal the significantly reduced diversity of FIV subtype B compared to that of other subtypes, which may associate with the low pathogenicity of this subtype. We also demonstrate that FIV subtype B Vif is less active with regard to feline APOBEC3 degradation. More intriguingly, we further reveal that FIV protease cleaves feline APOBEC3 in released virions. Taken together, our findings provide evidence that a lentivirus encodes two types of anti-APOBEC3 factors, Vif and viral protease. IMPORTANCE During the history of mammalian evolution, mammals coevolved with retroviruses, including lentiviruses. All pathogenic lentiviruses, excluding equine infectious anemia virus, have acquired the vif gene via evolution to combat APOBEC3 proteins, which are intrinsic restriction factors against exogenous lentiviruses. Here we demonstrate that FIV, a pathogenic lentivirus in domestic cats, antagonizes feline APOBEC3

  12. Orexin Receptor Antagonism Improves Sleep and Reduces Seizures in Kcna1-null Mice

    Science.gov (United States)

    Roundtree, Harrison M.; Simeone, Timothy A.; Johnson, Chaz; Matthews, Stephanie A.; Samson, Kaeli K.; Simeone, Kristina A.

    2016-01-01

    other epilepsy models. Citation: Roundtree HM, Simeone TA, Johnson C, Matthews SA, Samson KK, Simeone KA. Orexin receptor antagonism improves sleep and reduces seizures in Kcna1-null mice. SLEEP 2016;39(2):357–368. PMID:26446112

  13. Synthesis of C5-tetrazole derivatives of 2-amino-adipic acid displaying NMDA glutamate receptor antagonism.

    Science.gov (United States)

    Lenda, Fatimazohra; Crouzin, Nadine; Cavalier, Mélanie; Guiramand, Janique; Lanté, Fabien; Barbanel, Gérard; Cohen-Solal, Catherine; Martinez, Jean; Guenoun, Farhate; Lamaty, Frédéric; Vignes, Michel

    2011-03-01

    Five derivatives of 2-amino-adipic acid bearing a tetrazole-substituted in C5 position were synthesized. These compounds displayed selective antagonism towards N-methyl-D: -aspartate (NMDA) receptors compared with AMPA receptors, and they were devoid of any neurotoxicity. Among these five analogues, one exhibited a higher affinity for synaptic NMDA responses than the other four. Therefore, C5 tetrazole-substituted of 2-amino-adipic acid represent an interesting series of new NMDA receptor antagonists. This approach may be considered as a new strategy to develop ligands specifically targeted to synaptic or extra-synaptic NMDA receptors.

  14. Novel Bat Influenza Virus NS1 Proteins Bind Double-Stranded RNA and Antagonize Host Innate Immunity.

    Science.gov (United States)

    Turkington, Hannah L; Juozapaitis, Mindaugas; Kerry, Philip S; Aydillo, Teresa; Ayllon, Juan; García-Sastre, Adolfo; Schwemmle, Martin; Hale, Benjamin G

    2015-10-01

    We demonstrate that novel bat HL17NL10 and HL18NL11 influenza virus NS1 proteins are effective interferon antagonists but do not block general host gene expression. Solving the RNA-binding domain structures revealed the canonical NS1 symmetrical homodimer, and RNA binding required conserved basic residues in this domain. Interferon antagonism was strictly dependent on RNA binding, and chimeric bat influenza viruses expressing NS1s defective in this activity were highly attenuated in interferon-competent cells but not in cells unable to establish antiviral immunity. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  15. Analysis of geminivirus AL2 and L2 proteins reveals a novel AL2 silencing suppressor activity.

    Science.gov (United States)

    Jackel, Jamie N; Buchmann, R Cody; Singhal, Udit; Bisaro, David M

    2015-03-01

    Both posttranscriptional and transcriptional gene silencing (PTGS and TGS, respectively) participate in defense against the DNA-containing geminiviruses. As a countermeasure, members of the genus Begomovirus (e.g., Cabbage leaf curl virus) encode an AL2 protein that is both a transcriptional activator and a silencing suppressor. The related L2 protein of Beet curly top virus (genus Curtovirus) lacks transcription activation activity. Previous studies showed that both AL2 and L2 suppress silencing by a mechanism that correlates with adenosine kinase (ADK) inhibition, while AL2 in addition activates transcription of cellular genes that negatively regulate silencing pathways. The goal of this study was to clarify the general means by which these viral proteins inhibit various aspects of silencing. We confirmed that AL2 inhibits systemic silencing spread by a mechanism that requires transcription activation activity. Surprisingly, we also found that reversal of PTGS and TGS by ADK inactivation depended on whether experiments were conducted in vegetative or reproductive Nicotiana benthamiana plants (i.e., before or after the vegetative-to-reproductive transition). While AL2 was able to reverse silencing in both vegetative and reproductive plants, L2 and ADK inhibition were effective only in vegetative plants. This suggests that silencing maintenance mechanisms can change during development or in response to stress. Remarkably, we also observed that AL2 lacking its transcription activation domain could reverse TGS in reproductive plants, revealing a third, previously unsuspected AL2 suppression mechanism that depends on neither ADK inactivation nor transcription activation. RNA silencing in plants is a multivalent antiviral defense, and viruses respond by elaborating multiple and sometimes multifunctional proteins that inhibit various aspects of silencing. The studies described here add an additional layer of complexity to this interplay. By examining geminivirus AL2 and

  16. Integrating small molecule signalling and H-NS antagonism in Vibrio cholerae, a bacterium with two chromosomes.

    Science.gov (United States)

    Dorman, Charles J

    2015-08-01

    H-NS is a well-established silencer of virulence gene transcription in the human pathogen Vibrio cholerae. Biofilm formation aids V. cholerae in colonizing both its host and its external environments, and H-NS silences biofilm gene expression. Cyclic-di-guanosine monophosphate acts through the DNA binding proteins VpsR and VpsT to overcome H-NS-mediated repression of biofilm genes, driving a transition between a planktonic and a colonial/biofilm lifestyle. The H-NS binding pattern has now been charted on both chromosomes in V. cholerae, but whether or not this abundant DNA-binding-and-bridging protein plays any roles in nucleoid organization in this bacterium remains an open question. © 2015 John Wiley & Sons Ltd.

  17. Les voix du silence des rescapés de la Shoah : un retour à la vie ?

    Directory of Open Access Journals (Sweden)

    Fernande Ruiz Quemoun

    2015-11-01

    Full Text Available This paper shows the analysis of three autofiction comic books focussed on different silences of deported during and after the Shoah. The heros are Jewish children who survived hiding in silence thanks to the solidarity of the Righteous among the Nations. The analysis of these three comics, L'enfant cachée (Lizano, Dauvillier & Salsedo, Deuxième génération (Kichka and L’agneau qui ne voulait pas être un mouton (Jean & Zad, shows the voice of three survivors who man-aged to break their silence of more than sixty years. We will focus on the God silence, the silence of the rescued who prefers to say nothing, which right to say was denied, who has disappeared in ashes... We will emphasize the memorial literature of trials authors Wieviorka, Levinas and Friedemann, among others.

  18. Phenotyping of VIGS-mediated gene silencing in rice using a vector derived from a DNA virus.

    Science.gov (United States)

    Kant, Ravi; Dasgupta, Indranil

    2017-07-01

    Target genes in rice can be optimally silenced if inserted in antisense or hairpin orientation in the RTBV-derived VIGS vector and plants grown at 28 °C and 80% humidity after inoculation. Virus induced gene silencing (VIGS) is a method used to transiently silence genes in dicot as well as monocot plants. For the important monocot species rice, the Rice tungro bacilliform virus (RTBV)-derived VIGS system (RTBV-VIGS), which uses agroinoculation to initiate silencing, has not been standardized for optimal use. Here, using RTBV-VIGS, three sets of conditions were tested to achieve optimal silencing of the rice marker gene phytoene desaturase (pds). The effect of orientation of the insert in the RTBV-VIGS plasmid (sense, antisense and hairpin) on the silencing of the target gene was then evaluated using rice magnesium chelatase subunit H (chlH). Finally, the rice Xa21 gene, conferring resistance against bacterial leaf blight disease (BLB) was silenced using RTBV-VIGS system. In each case, real-time PCR-based assessment indicated approximately 40-80% fall in the accumulation levels of the transcripts of pds, chlH and Xa21. In the case of pds, the appearance of white streaks in the emerging leaves, and for chlH, chlorophyll levels and F v /F m ratio were assessed as phenotypes for silencing. For Xa21, the resistance levels to BLB were assessed by measuring the lesion length and the percent diseased areas of leaves, following challenge inoculation with Xanthomonas oryzae. In each case, the RTBV-MVIGS system gave rise to a discernible phenotype indicating the silencing of the respective target gene using condition III (temperature 28 °C, humidity 80% and 1 mM MES and 20 µM acetosyringone in secondary agrobacterium culture), which revealed the robustness of this gene silencing system for rice.

  19. Development of male sterility by silencing Bcp1 gene of Arabidopsis ...

    African Journals Online (AJOL)

    The development of male sterility is one of the most important steps in hybrid seed production. Several methods for the abortion of pollens based on conventional as well as genetic engineering are reported for the various crop species. Here we have investigated the use of RNA interference (RNAi) technology to silence a ...

  20. KDR gene silencing inhibits proliferation of A549 cells and enhances their sensitivity to docetaxel.

    Science.gov (United States)

    Wei, R; Zang, J-P

    2015-11-23

    We investigated the effects of kinase-domain insert containing receptor (KDR) gene silencing on the proliferation of A549 cells and their sensitivity to docetaxel. After designing and synthesizing the KDR siRNA sequence, the sequence was transfected into A549 cells using Lipofectamine 2000. The expression of KDR mRNA and protein after KDR gene silencing was detected by reverse transcription-polymerase chain reaction and western blotting; A549 cell cycle was detected by flow cytometry. An MTT assay and colony formation was performed to determine the sensitivity of A549 cells to docetaxel after KDR gene silencing. After 48-h KDR gene silencing, KDR gene and protein expression significantly decreased (P A549 cell cycle was significantly arrested in G0/G1 phase, and the number of cells in S phase was reduced; the difference was statistically significant (P A549 cells to docetaxel showed a significant enhancement (P A549 cells, inhibit the proliferation of A549 cells, and enhance their sensitivity to docetaxel.

  1. Silencing of TGIF attenuates the tumorigenicity of A549 cells in vitro and in vivo.

    Science.gov (United States)

    Wang, Yadong; Pan, Teng; Wang, Haiyu; Li, Li; Li, Jiangmin; Zhang, Congke; Yang, Haiyan

    2016-09-01

    The aim of this study was to investigate the effects of the silencing of the TG-interacting factor (TGIF) on the tumorigenicity of A549 cells in vitro and in vivo. Stable TGIF-silenced A549 cells were established by infecting shRNA lentiviral particles. Western blotting analysis was used to detect the expression of proteins. Cell cycle was detected by flow cytometry. Soft agar assay and tumor formation assay in nude mice were applied. The silencing of TGIF inhibited A549 cell proliferation, colony formation in vitro, growth of tumor xenograft in vivo, and arrested the cell cycle in the G1 phase. The expression of CDK4, cyclin D1, and phospho-Rb was markedly decreased in the A549-shTGIF cells compared with the A549-shcon cells, and p21 was markedly increased in the A549-shTGIF cells compared with the A549-shcon cells. A lower level of β-Catenin protein expression was observed in the A549-shTGIF cells than that in the A549-shcon cells. The silencing of TGIF attenuates the tumorigenicity of A549 cells in vitro and in vivo.

  2. Gene silencing of stearoyl-ACP desaturase enhances the stearic acid content in Chlamydomonas reinhardtii

    NARCIS (Netherlands)

    Jaeger, de L.; Springer, J.; Wolbert, E.J.H.; Martens, D.E.; Eggink, G.; Wijffels, R.H.

    2017-01-01

    In this study, stearoyl-ACP desaturase (SAD), the enzyme that converts stearic acid into oleic acid, is silenced by artificial microRNA in the green microalga Chlamydomonas reinhardtii. Two different constructs, which target different positions on the mRNA of stearoyl-ACP desaturase, were tested.

  3. The Relationship among Interactional Justice, Manager Trust and Teachers' Organizational Silence Behavior

    Science.gov (United States)

    Yangin, Demet; Elma, Cevat

    2017-01-01

    The purpose of this study was to determine the relationship between the manager trust and interactional justice perceptions and organizational silence behaviors of those teachers who work in primary and secondary schools. The research is based on the survey model and the population consists of 4761 teachers who worked in Samsun, Turkey. The sample…

  4. A Day of Silence, a Day of Truth, and a Lawsuit

    Science.gov (United States)

    Fusarelli, Bonnie C.; Eaton, Lucy E.

    2011-01-01

    This case study focuses on issues of freedom of speech and freedom of religion in public schools. It involves a rural, southern high school where a group of students participated in a Day of Silence. The school allowed the students to participate based on the principal's understanding of the students' First Amendment rights. However, the next day,…

  5. 'Checkmating HIV&AIDS': Using chess to break the silence in the ...

    African Journals Online (AJOL)

    In this article, I give an account of my 'Checkmating HIV&AIDS' action research project, which was an attempt to break the 'culture of silence' concerning HIV&AIDS and sex and sexuality in my classroom. In this project, I focused specifically on one code of sport, namely chess, and I point out and discuss the potential of ...

  6. [Effects of Sam68 gene silence on proliferation of acute T lymphoblastic leukemia cell line Jurkat].

    Science.gov (United States)

    Wang, Chi-Juan; Xu, Hua; Zhang, Hai-Rui; Wang, Jian; Lin, Ya-Ni; Pang, Tian-Xiang; Li, Qing-Hua

    2014-08-01

    This study was purpose to investigate the effect of Sam68 gene silence on proliferation of human acute T lymphoblastic leukemia cell line Jurkat. The sequence of shRNA targeting the site 531-552 of Sam68 mRNA was designed and chemically synthesized, then a single-vector lentiviral, Tet-inducible shRNA-Sam68 system (pLKO-Tet-On) was constructed; next the Jurkat cells were infected with lentivirus to create stable cell clones with regulatable Sam68 gene expression. The inhibitory efficiency of Sam68 gene was assayed by Real-time PCR and Western blot; the cell activity of Jurkat cells was detected with MTT assay; the change of colony forming potential of Jurkat cells was analyzed by colony forming test; the cell cycle distribution was tested by flow cytometry. The results indicated that the expression of Sam68 in experimental cells was statistically decreased as compared with that of the control cells; the cells activity and colony forming capacity of the Jurkat cells with Sam68 gene silence were significantly inhibited; with Sam68 gene silencing, the percentage of S phase cells was significantly increased, while the percentage of G2 phase cells was significantly decreased. It is concluded that the silencing Sam68 gene using shRNA interference can effectively inhibit the proliferation of human acute T lymphoblastic leukemia cell line Jurkat.

  7. The New Role of Librarians and Libraries: Removing the Silence Signs

    Science.gov (United States)

    Carriuolo, Nancy; Reis, Tovah

    2015-01-01

    An increasing number of institutions are freeing up shelf space in their libraries and moving in student services as well as a coffee shop and other lures such as flexible seating arrangements. Librarians are taking down the silence signs in all but the quiet study room and urging members of the academic community to meet, talk, research and…

  8. ADAM17 silencing in mouse colon carcinoma cells: the effect on tumoricidal cytokines and angiogenesis.

    Directory of Open Access Journals (Sweden)

    Sudipta Das

    Full Text Available ADAM17 (a disintegrin and metalloprotease 17 is a major sheddase for numerous growth factors, cytokines, receptors, and cell adhesion molecules and is often overexpressed in malignant cells. It is generally accepted that ADAM17 promotes tumor development via activating growth factors from the EGF family, thus facilitating autocrine stimulation of tumor cell proliferation and migration. Here we show, using MC38CEA murine colon carcinoma model, that ADAM17 also regulates tumor angiogenesis and cytokine profile. When ADAM17 was silenced in MC38CEA cells, in vivo tumor growth and in vitro cell motility were significantly diminished, but no effect was seen on in vitro cell proliferation. ADAM17-silencing was accompanied by decreased in vitro expression of vascular endothelial growth factor-A and matrix metalloprotease-9, which was consistent with the limited angiogenesis and slower growth seen in ADAM17-silenced tumors. Among the growth factors susceptible to shedding by ADAM17, neuregulin-1 was the only candidate to mediate the effects of ADAM17 on MC38CEA motility and tumor angiogenesis. Concentrations of TNF and IFNγ, cytokines that synergistically induced proapoptotic effects on MC38CEA cells, were significantly elevated in the lysates of ADAM17-silenced tumors compared to mock transfected controls, suggesting a possible role for ADAM17 in host immune suppression. These results introduce new, complex roles of ADAM17 in tumor progression, including its impact on the anti-tumor immune response.

  9. Improving self-directed learning/intercultural competencies: breaking the silence.

    Science.gov (United States)

    Kirkpatrick, Mary K; Esterhuizen, Philip; Jesse, Elizabeth; Brown, Sylvia T

    2015-01-01

    Nurse educators need to develop innovative, technological curricula that foster intercultural competencies as essential components of a university education and break the silence with respect to lesbian, gay, bisexual, transgender, and queer (LGBTQ) health. Goals are to foster using these competencies to make LGBTQ content explicit in nursing curricula and in their professional organizations to promote equality and lessen disparities in this group.

  10. DNA replication factor C1 mediates genomic stability and transcriptional gene silencing in Arabidopsis

    KAUST Repository

    Liu, Qian

    2010-07-01

    Genetic screening identified a suppressor of ros1-1, a mutant of REPRESSOR OF SILENCING1 (ROS1; encoding a DNA demethylation protein). The suppressor is a mutation in the gene encoding the largest subunit of replication factor C (RFC1). This mutation of RFC1 reactivates the unlinked 35S-NPTII transgene, which is silenced in ros1 and also increases expression of the pericentromeric Athila retrotransposons named transcriptional silent information in a DNA methylationindependent manner. rfc1 is more sensitive than the wild type to the DNA-damaging agent methylmethane sulphonate and to the DNA inter- and intra- cross-linking agent cisplatin. The rfc1 mutant constitutively expresses the G2/M-specific cyclin CycB1;1 and other DNA repair-related genes. Treatment with DNA-damaging agents mimics the rfc1 mutation in releasing the silenced 35S-NPTII, suggesting that spontaneously induced genomic instability caused by the rfc1 mutation might partially contribute to the released transcriptional gene silencing (TGS). The frequency of somatic homologous recombination is significantly increased in the rfc1 mutant. Interestingly, ros1 mutants show increased telomere length, but rfc1 mutants show decreased telomere length and reduced expression of telomerase. Our results suggest that RFC1 helps mediate genomic stability and TGS in Arabidopsis thaliana. © 2010 American Society of Plant Biologists.

  11. Shattering the silence: IDRC-Zubaan research speaks out on sexual ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2016-06-14

    Jun 14, 2016 ... The silence surrounding sexual violence in South Asia has been shattered. The Zubaan Series on Sexual Violence and Impunity in South Asia, formally launched in New Delhi on May 21, 2016, presents severe statements about criminal justice systems in South Asia that turn their back on sexual violence, ...

  12. Silencing of the SlNAP7 gene influences plastid development and lycopene accumulation in tomato

    Science.gov (United States)

    Fu, Da-Qi; Meng, Lan-Huan; Zhu, Ben-Zhong; Zhu, Hong-Liang; Yan, Hua-Xue; Luo, Yun-Bo

    2016-12-01

    Ripening is an important stage of fruit development. To screen the genes associated with pigment formation in tomato fruit, a suppression subtractive hybridization (SSH) cDNA library was constructed by using tomato fruit in the green ripe and break ripe stages, and 129 differential genes were obtained. Using redness as a screening marker, virus-induced gene silencing (VIGS) of the differential genes was performed with a sprout vacuum-infiltration system (SVI). The results showed that silencing the SlNAP7 gene affected the chloroplast development of tomato leaves, manifesting as a photo-bleaching phenotype, and silenced fruit significantly affected the accumulation of lycopene, manifested as a yellow phenotype. In our study, we found that silencing the SlNAP7 gene downregulates the expression of the POR and PORA genes and destroys the normal development of the chloroplast. The expression of related genes included in the lycopene biosynthesis pathway was not significantly changed, but lycopene accumulation was significantly reduced in tomato fruit. Perhaps it was caused by the destruction of the chromoplast, which leads to the oxidation of lycopene. The results show that the SlNAP7 gene influences chloroplast development and lycopene accumulation in tomato.

  13. Graft-accelerated virus-induced gene silencing facilitates functional genomics in rose flowers.

    Science.gov (United States)

    Yan, Huijun; Shi, Shaochuan; Ma, Nan; Cao, Xiaoqian; Zhang, Hao; Qiu, Xianqin; Wang, Qigang; Jian, Hongying; Zhou, Ningning; Zhang, Zhao; Tang, Kaixue

    2018-01-01

    Rose has emerged as a model ornamental plant for studies of flower development, senescence, and morphology, as well as the metabolism of floral fragrances and colors. Virus-induced gene silencing (VIGS) has long been used in functional genomics studies of rose by vacuum infiltration of cuttings or seedlings with an Agrobacterium suspension carrying TRV-derived vectors. However, VIGS in rose flowers remains a challenge because of its low efficiency and long time to establish silencing. Here we present a novel and rapid VIGS method that can be used to analyze gene function in rose, called 'graft-accelerated VIGS', where axillary sprouts are cut from the rose plant and vacuum infiltrated with Agrobacterium. The inoculated scions are then grafted back onto the plants to flower and silencing phenotypes can be observed within 5 weeks, post-infiltration. Using this new method, we successfully silenced expression of the RhDFR1, RhAG, and RhNUDX1 in rose flowers, and affected their color, petal number, as well as fragrance, respectively. This grafting method will facilitate high-throughput functional analysis of genes in rose flowers. Importantly, it may also be applied to other woody species that are not currently amenable to VIGS by conventional leaf or plantlet/seedling infiltration methods. © 2017 Institute of Botany, Chinese Academy of Sciences.

  14. Silencing Agrobacterium oncogenes in transgenic grapevine results in strain-specific crown gall resistance.

    Science.gov (United States)

    Galambos, A; Zok, A; Kuczmog, A; Oláh, R; Putnoky, P; Ream, W; Szegedi, E

    2013-11-01

    Grapevine rootstock transformed with an Agrobacterium oncogene-silencing transgene was resistant to certain Agrobacterium strains but sensitive to others. Thus, genetic diversity of Agrobacterium oncogenes may limit engineering crown gall resistance. Crown gall disease of grapevine induced by Agrobacterium vitis or Agrobacterium tumefaciens causes serious economic losses in viticulture. To establish crown gall-resistant lines, somatic proembryos of Vitis berlandieri × V. rupestris cv. 'Richter 110' rootstock were transformed with an oncogene-silencing transgene based on iaaM and ipt oncogene sequences from octopine-type, tumor-inducing (Ti) plasmid pTiA6. Twenty-one transgenic lines were selected, and their transgenic nature was confirmed by polymerase chain reaction (PCR). These lines were inoculated with two A. tumefaciens and three A. vitis strains. Eight lines showed resistance to octopine-type A. tumefaciens A348. Resistance correlated with the expression of the silencing genes. However, oncogene silencing was mostly sequence specific because these lines did not abolish tumorigenesis by A. vitis strains or nopaline-type A. tumefaciens C58.

  15. Silence, pleasure and agency: sexuality of unmarried girls in Dakar, Senegal

    NARCIS (Netherlands)

    Eerdewijk, A.H.J.M. van

    2009-01-01

    The article investigates the way unmarried Muslim girls in contemporary Dakar construct their sexuality. It explores in what way and to what extent female sexuality is being silenced, and if any, in what way pleasure and sexual agency are present in the narratives of those girls about their intimate

  16. Spatio-temporal requirements for transposable element piRNA-mediated silencing during Drosophila oogenesis.

    Science.gov (United States)

    Dufourt, Jérémy; Dennis, Cynthia; Boivin, Antoine; Gueguen, Nathalie; Théron, Emmanuelle; Goriaux, Coline; Pouchin, Pierre; Ronsseray, Stéphane; Brasset, Emilie; Vaury, Chantal

    2014-02-01

    During Drosophila oogenesis, transposable element (TE) repression involves the Piwi-interacting RNA (piRNA) pathway which ensures genome integrity for the next generation. We developed a transgenic model to study repression of the Idefix retrotransposon in the germline. Using a candidate gene KD-approach, we identified differences in the spatio-temporal requirements of the piRNA pathway components for piRNA-mediated silencing. Some of them (Aub, Vasa, Spn-E) are necessary in very early stages of oogenesis within the germarium and appear to be less important for efficient TE silencing thereafter. Others (Piwi, Ago3, Mael) are required at all stages of oogenesis. Moreover, during early oogenesis, in the dividing cysts within the germarium, Idefix anti-sense transgenes escape host control, and this is associated with very low piwi expression. Silencing of P-element-based transgenes is also strongly weakened in these cysts. This region, termed the 'Piwiless pocket' or Pilp, may ensure that new TE insertions occur and are transmitted to the next generation, thereby contributing to genome dynamics. In contrast, piRNA-mediated silencing is strong in germline stem cells in which TE mobilization is tightly repressed ensuring the continued production of viable germline cysts.

  17. The shadow of silence on the sexual rights of married Iranian women.

    Science.gov (United States)

    Janghorban, Roksana; Latifnejad Roudsari, Robab; Taghipour, Ali; Abbasi, Mahmoud; Lottes, Ilsa

    2015-01-01

    There has been a recent shift in the field of sexual health, representing a move away from biomedical concerns to sexual rights frameworks. However, few studies on sexuality are based on a rights framework. The unspoken nature of sexuality in Iranian culture has led to a lack of national studies on the topic. The objective of this study was to explore the perceptions and experiences of married Iranian women on sexual rights in their sexual relationships. In this grounded theory study, 37 participants (25 married women, 5 husbands, and 7 midwives) were selected. Data were collected through in-depth interviews and analyzed through open, axial, and selective coding using MAXQDA software version 2007. The analysis revealed the core category of "sexual interaction in the shadow of silence." The interrelated categories subsumed under the core category included adopting a strategy of silence, trying to negotiate sex, seeking help, and sexual adjustment. The silence originating from women's interactions with their families and society, from girlhood to womanhood, was identified as the core concept in Iranian women's experiences of sexual rights. A focus on husbands' roles seems salient because they can direct or alter some learned feminine roles, especially silence regarding sexual matters, which then affects the realization of women's sexual rights.

  18. Performances of Student Activism: Sound, Silence, Gender, and Dis/ability

    Science.gov (United States)

    Pasque, Penny A.; Vargas, Juanita Gamez

    2014-01-01

    This chapter explores the various performances of activism by students through sound, silence, gender, and dis/ability and how these performances connect to social change efforts around issues such as human trafficking, homeless children, hunger, and children with varying abilities.

  19. Phenotypic changes associated with RNA interference silencing of chalcone synthase in apple (Malus × domestica).

    Science.gov (United States)

    Dare, Andrew P; Tomes, Sumathi; Jones, Midori; McGhie, Tony K; Stevenson, David E; Johnson, Ross A; Greenwood, David R; Hellens, Roger P

    2013-05-01

    We have identified in apple (Malus × domestica) three chalcone synthase (CHS) genes. In order to understand the functional redundancy of this gene family RNA interference knockout lines were generated where all three of these genes were down-regulated. These lines had no detectable anthocyanins and radically reduced concentrations of dihydrochalcones and flavonoids. Surprisingly, down-regulation of CHS also led to major changes in plant development, resulting in plants with shortened internode lengths, smaller leaves and a greatly reduced growth rate. Microscopic analysis revealed that these phenotypic changes extended down to the cellular level, with CHS-silenced lines showing aberrant cellular organisation in the leaves. Fruit collected from one CHS-silenced line was smaller than the 'Royal Gala' controls, lacked flavonoids in the skin and flesh and also had changes in cell morphology. Auxin transport experiments showed increased rates of auxin transport in a CHS-silenced line compared with the 'Royal Gala' control. As flavonoids are well known to be key modulators of auxin transport, we hypothesise that the removal of almost all flavonoids from the plant by CHS silencing creates a vastly altered environment for auxin transport to occur and results in the observed changes in growth and development. © 2013 The Authors The Plant Journal © 2013 Blackwell Publishing Ltd.

  20. The Relationship between Organizational Climate and the Organizational Silence of Administrative Staff in Education Department

    Science.gov (United States)

    Pozveh, Asghar Zamani; Karimi, Fariba

    2016-01-01

    The aim of the present study was to determine the relationship between organizational climate and the organizational silence of administrative staff in Education Department in Isfahan. The research method was descriptive and correlational-type method. The study population was administrative staff of Education Department in Isfahan during the…

  1. In trans silencing properties of a tobacco transgene locus depend on its epigenetic state

    Czech Academy of Sciences Publication Activity Database

    Fojtová, Miloslava; Van Houdt, H.; Depicker, A.; Kovařík, Aleš

    2004-01-01

    Roč. 26, č. 3 (2004), s. 147 ISSN 0137-5881. [Congress of the Federation of European Societies of Plant Biology /14./. 23.08.2004-27.08.2004, Cracow] Keywords : plant transgenes * gene expression * silencing Subject RIV: BO - Biophysics

  2. Telomere Position Effect and Silencing of Transgenes near Telomeres in the Mouse¶

    Science.gov (United States)

    Pedram, Mehrdad; Sprung, Carl N.; Gao, Qing; Lo, Anthony W. I.; Reynolds, Gloria E.; Murnane, John P.

    2006-01-01

    Reversible transcriptional silencing of genes located near telomeres, termed the telomere position effect (TPE), is well characterized in Saccharomyces cerevisiae. TPE has also been observed in human tumor cell lines, but its function remains unknown. To investigate TPE in normal mammalian cells, we developed clones of mouse embryonic stem (ES) cells that contain single-copy marker genes integrated adjacent to different telomeres. Analysis of these telomeric transgenes demonstrated that they were expressed at very low levels compared to the same transgenes integrated at interstitial sites. Similar to the situation in yeast, but in contrast to studies with human tumor cell lines, TPE in mouse ES cells was not reversed with trichostatin A. Prolonged culturing without selection resulted in extensive DNA methylation and complete silencing of telomeric transgenes, which could be reversed by treatment with 5-azacytidine. Thus, complete silencing of the telomeric transgenes appears to involve a two-step process in which the initial repression is reinforced by DNA methylation. Extensive methylation of the telomeric transgenes was also observed in various tissues and embryonic fibroblasts isolated from transgenic mice. In contrast, telomeric transgenes were not silenced in ES cell lines isolated from 3-day-old preimplantation embryos, consistent with the hypothesis that TPE plays a role in the development of the embryo. PMID:16479005

  3. Transient receptor potential vanilloid 4 (TRPV4) silencing in Helicobacter pylori-infected human gastric epithelium.

    Science.gov (United States)

    Mihara, Hiroshi; Suzuki, Nobuhiro; Muhammad, Jibran Sualeh; Nanjo, Sohachi; Ando, Takayuki; Fujinami, Haruka; Kajiura, Shinya; Hosokawa, Ayumu; Sugiyama, Toshiro

    2017-04-01

    Helicobacter pylori (HP) infection induces methylation silencing of specific genes in gastric epithelium. Various stimuli activate the nonselective cation channel TRPV4, which is expressed in gastric epithelium where it detects mechanical stimuli and promotes ATP release. As CpG islands in TRPV4 are methylated in HP-infected gastric epithelium, we evaluated HP infection-dependent changes in TRPV4 expression in gastric epithelium. Human gastric biopsy samples, a human gastric cancer cell line (AGS), and a normal gastric epithelial cell line (GES-1) were used to detect TRPV4 mRNA and protein expression by RT-PCR and Western blotting, respectively. Ca 2+ imaging was used to evaluate TRPV4 ion channel activity. TRPV4 methylation status was assessed by methylation-specific PCR (MSP). ATP release was measured by a luciferin-luciferase assay. TRPV4 mRNA and protein were detected in human gastric biopsy samples and in GES-1 cells. MSP and demethylation assays showed TRPV4 methylation silencing in AGS cells. HP coculture directly induced methylation silencing of TRPV4 in GES-1 cells. In human samples, HP infection was associated with TRPV4 methylation silencing that recovered after HP eradication in a time-dependent manner. HP infection-dependent DNA methylation suppressed TRPV4 expression in human gastric epithelia, suggesting that TRPV4 methylation may be involved in HP-associated dyspepsia. © 2016 The Authors. Helicobacter Published by John Wiley & Sons Ltd.

  4. Socrates, Augustine, and Paul Gauguin on the Reciprocity between Speech and Silence in Education

    Science.gov (United States)

    Caranfa, Angelo

    2013-01-01

    While most educational practices today place an excessive amount of attention on discourse, this article attaches great importance to the reciprocity between speech and silence by drawing from the writings of Plato's Socrates, Augustine, and Paul Gauguin for whom this reciprocity is of the essence in learning. These three figures teach that…

  5. Silencing effect of shRNA expression vectors with stem length of 21 ...

    African Journals Online (AJOL)

    In this study, shRNA vectors having different stem length were constructed and their silencing effect was tested in mouse embryonic fibroblast and in vivo. Interfering RNAs were designed with stems of 21, 27, and 29 bp. The enhanced green fluorescent protein gene was used as target gene. The synthesized single strands ...

  6. The potential of virus-induced gene silencing for speeding up functional characterization of plant genes

    NARCIS (Netherlands)

    Benedito, V.A.; Visser, P.B.; Angenent, G.C.; Krens, F.A.

    2004-01-01

    Virus-induced gene silencing (VIGS) has been shown to be of great potential in plant reverse genetics. Advantages of VIGS over other approaches, such as T-DNA or transposon tagging, include the circumvention of plant transformation, methodological simplicity and robustness, and speedy results. These

  7. Silencing an Anopheles gambiae Catalase and Sulfhydryl Oxidase Increases Mosquito Mortality After a Blood Meal

    Science.gov (United States)

    Magalhaes, T.; Brackney, D.E.; Beier, J.C.; Foy, B.D.

    2009-01-01

    Catalase is a potent antioxidant, likely involved in post-blood meal homeostasis in mosquitoes. This enzyme breaks down H2O2, preventing the formation of the hydroxyl radical (HO•). Quiescins are newly classified sulfhydryl oxidases that bear a thioredoxin motif at the N-terminal and an ERV1-like portion at the C-terminal. These proteins have a major role in generating disulfides in intra- or extracellular environments, and thus participate in redox reactions. In the search for molecules to serve as targets for novel anti-mosquito strategies, we have silenced a catalase and a putative quiescin/sulfhydryl oxidase (QSOX), from the African malaria vector Anopheles gambiae, through RNA interference (RNAi) experiments. We observed that the survival of catalase- and QSOX-silenced insects was reduced over controls following blood digestion, most likely due to the compromised ability of mosquitoes to scavenge and/or prevent damage caused by blood meal-derived oxidative stress. The higher mortality effect was more accentuated in catalase-silenced mosquitoes, where catalase activity was reduced to low levels. Lipid peroxidation was higher in QSOX-silenced mosquitoes suggesting the involvement of this protein in redox homeostasis following a blood meal. This study points to the potential of molecules involved in antioxidant response and redox metabolism to serve as targets of novel anti-mosquito strategies and offers a screening methodology for finding targetable mosquito molecules. PMID:18454489

  8. Between Silence and Speech: Autoethnography as an Otherness-Resisting Practice

    Science.gov (United States)

    Tsalach, Calanit

    2013-01-01

    In this article I wish to trace three everyday moments in which my Mizrahi Ethnic Identity intersects with the academic one, and then extract experiences of ethnic otherness that are built within those moments. Exploring these moments while considering Mizrahi identity construction, practices of otherness, and terms of silences enables a more…

  9. After Brown U.'s Report on Slavery, Silence (So Far)

    Science.gov (United States)

    Bartlett, Thomas

    2006-01-01

    This article, discusses Brown University's slavery report, a 106-page narrative examination of the early connections between Brown University and slavery, that has been greeted--so far--with silence. The report, done at the behest of Ruth J. Simmons, Brown's president and herself a descendant of slaves, is an unsparing look at a shameful side of…

  10. An Eastern Learning Paradox: Paradoxes in Two Korean Mathematics Teachers' Pedagogy of Silence in the Classroom

    Science.gov (United States)

    Lee, Kyeonghwa; Sriraman, Bharath

    2013-01-01

    Eastern philosophies of education such as Confucianism and Taosim advocate the use of silence in the teacher-pupil tradition of pedagogy. We investigate contemporary classrooms in Korea, and study whether teachers in Korea today incorporate this method implicitly or explicitly in their classrooms. Empirical data in the form of video-taped…

  11. Hearing Silence: Toward a Mixed-Method Approach for Studying Genres' Exclusionary Potential

    Science.gov (United States)

    Randazzo, Chalice

    2015-01-01

    Traditional Rhetorical Genre Study (RGS) methods are not well adapted to study exclusion because excluded information and people are typically absent from the genre, and some excluded information is simply unrelated to the genre because of genre conventions or social context. Within genre-based silences, how can scholars differentiate between an…

  12. Novel RNA Duplex Locks HIV-1 in a Latent State via Chromatin-mediated Transcriptional Silencing

    Directory of Open Access Journals (Sweden)

    Chantelle Ahlenstiel

    2015-01-01

    Full Text Available Transcriptional gene silencing (TGS of mammalian genes can be induced by short interfering RNA (siRNA targeting promoter regions. We previously reported potent TGS of HIV-1 by siRNA (PromA, which targets tandem NF-κB motifs within the viral 5′LTR. In this study, we screened a siRNA panel with the aim of identifying novel 5′LTR targets, to provide multiplexing potential with enhanced viral silencing and application toward developing alternate therapeutic strategies. Systematic examination identified a novel siRNA target, si143, confirmed to induce TGS as the silencing mechanism. TGS was prolonged with virus suppression >12 days, despite a limited ability to induce post- TGS. Epigenetic changes associated with silencing were suggested by partial reversal by histone deacetylase inhibitors and confirmed by chromatin immunoprecipitation analyses, which showed induction of H3K27me3 and H3K9me3, reduction in H3K9Ac, and recruitment of argonaute-1, all characteristic marks of heterochromatin and TGS. Together, these epigenetic changes mimic those associated with HIV-1 latency. Further, robust resistance to reactivation was observed in the J-Lat 9.2 cell latency model, when transduced with shPromA and/or sh143. These data support si/shRNA-mediated TGS approaches to HIV-1 and provide alternate targets to pursue a functional cure, whereby the viral reservoir is locked in latency following antiretroviral therapy cessation.

  13. The Shadow of Silence on the Sexual Rights of Married Iranian Women

    Directory of Open Access Journals (Sweden)

    Roksana Janghorban

    2015-01-01

    Full Text Available There has been a recent shift in the field of sexual health, representing a move away from biomedical concerns to sexual rights frameworks. However, few studies on sexuality are based on a rights framework. The unspoken nature of sexuality in Iranian culture has led to a lack of national studies on the topic. The objective of this study was to explore the perceptions and experiences of married Iranian women on sexual rights in their sexual relationships. In this grounded theory study, 37 participants (25 married women, 5 husbands, and 7 midwives were selected. Data were collected through in-depth interviews and analyzed through open, axial, and selective coding using MAXQDA software version 2007. The analysis revealed the core category of “sexual interaction in the shadow of silence.” The interrelated categories subsumed under the core category included adopting a strategy of silence, trying to negotiate sex, seeking help, and sexual adjustment. The silence originating from women’s interactions with their families and society, from girlhood to womanhood, was identified as the core concept in Iranian women’s experiences of sexual rights. A focus on husbands’ roles seems salient because they can direct or alter some learned feminine roles, especially silence regarding sexual matters, which then affects the realization of women’s sexual rights.

  14. CRISPR Interference Efficiently Induces Specific and Reversible Gene Silencing in Human iPSCs

    DEFF Research Database (Denmark)

    Mandegar, Mohammad A.; Huebsch, Nathaniel; Frolov, Ekaterina B.

    2016-01-01

    repression system is tunable and has the potential to silence single alleles. Compared with CRISPR nuclease (CRISPRn), CRISPRi gene repression is more efficient and homogenous across cell populations. The CRISPRi system in iPSCs provides a powerful platform to perform genome-scale screens in a wide range...

  15. Silence in Official Representations of History: Implications for National Identity and Intergroup Relations

    Directory of Open Access Journals (Sweden)

    Tuğçe Kurtiş

    2018-01-01

    Full Text Available Dominant representations of history evolve through differential exercise of power to enable memory of collective triumphs and silence memory of collective misdeeds. We examined silence regarding minorities in official constructions of history and the implications of this silence for national identity and intergroup relations in Turkey. A content analysis of official constructions of history inscribed in Turkish national university admissions exams (Study 1 revealed an emphasis on celebratory events, silence about ethnic and religious minorities, and a construction of national identity in ethno-cultural (e.g., as “Turk” and “Muslim” rather than civic terms (e.g., in terms of citizenship. An investigation with Turkish participants (Study 2 revealed that denial of historical information regarding minority populations documented in sources outside the national curriculum was associated with greater endorsement of ethno-cultural constructions of identity and less support for minority rights and freedom of expression. We discuss the liberatory potential of alternative forms of historical knowledge to promote more inclusive models of identification and improve intergroup relations.

  16. On the Grammar of Silence: The Structure of My Undocumented Immigrant Writer's Block

    Science.gov (United States)

    Ledesma, Alberto

    2015-01-01

    In this reflective essay, Alberto Ledesma explores how being undocumented can produce a particular form of writer's block. He argues that there is a pattern of predictable silences and obfuscations inherent in all undocumented immigrant autobiographies that cannot be easily negotiated when undocumented students are asked to write about "their…

  17. Voicing and silence periods in daily and weekly vocalizations of teachers

    NARCIS (Netherlands)

    Titze, Ingo R.; Hunter, Eric J.; Svec, Jan G.

    The National Center for Voice and Speech (NCVS) data bank on voice dosimetry was used to study the distributions of continuous voicing periods and silence periods in 31 teachers over the duration of two weeks. Recordings were made during all awake hours of the day. Voicing periods were grouped into

  18. Breaking the culture of silence in checkmating HIV/AIDS as a ...

    African Journals Online (AJOL)

    In my investigation I set out to break the HIV/AIDS culture of silence and emphasize the role of the teacher as a researcher and critical change agent in an HIV/AIDS challenged society. My work demonstrates how teachers could play such a role by encouraging learners' participation in sport. The sport, I focussed on in my ...

  19. The splicing machinery promotes RNA-directed DNA methylation and transcriptional silencing in Arabidopsis

    Science.gov (United States)

    Zhang, Cui-Jun; Zhou, Jin-Xing; Liu, Jun; Ma, Ze-Yang; Zhang, Su-Wei; Dou, Kun; Huang, Huan-Wei; Cai, Tao; Liu, Renyi; Zhu, Jian-Kang; He, Xin-Jian

    2013-01-01

    DNA methylation in transposons and other DNA repeats is conserved in plants as well as in animals. In Arabidopsis thaliana, an RNA-directed DNA methylation (RdDM) pathway directs de novo DNA methylation. We performed a forward genetic screen for suppressors of the DNA demethylase mutant ros1 and identified a novel Zinc-finger and OCRE domain-containing Protein 1 (ZOP1) that promotes Pol IV-dependent siRNA accumulation, DNA methylation, and transcriptional silencing. Whole-genome methods disclosed the genome-wide effects of zop1 on Pol IV-dependent siRNA accumulation and DNA methylation, suggesting that ZOP1 has both RdDM-dependent and -independent roles in transcriptional silencing. We demonstrated that ZOP1 is a pre-mRNA splicing factor that associates with several typical components of the splicing machinery as well as with Pol II. Immunofluorescence assay revealed that ZOP1 overlaps with Cajal body and is partially colocalized with NRPE1 and DRM2. Moreover, we found that the other development-defective splicing mutants tested including mac3a3b, mos4, mos12 and mos14 show defects in RdDM and transcriptional silencing. We propose that the splicing machinery rather than specific splicing factors is involved in promoting RdDM and transcriptional silencing. PMID:23524848

  20. "Making a Way": Young Women Using Literacy and Language to Resist the Politics of Silencing

    Science.gov (United States)

    Wissman, Kelly K.

    2007-01-01

    Urban public schools are often contexts in which students are beset with silencing, surveillance, and low expectations. These conditions present distinct and critical challenges to young women. This article explores the language and literacy practices that emerged in an in-school elective writing and photography course designed with and for young…